Knowledge Center

14K
By weight 14 parts gold to 10 parts other metals, or 58.33% pure gold see 585.

 

18K
By weight 18 parts gold to 6 parts other metals, or 75.0% pure gold, marked 750 or 18K.

 

22K
By weight 22 parts gold to 2 parts other metals, or 91.66% pure gold, marked 22K

 

585
So called London gold, the British 14K standard is slightly higher than the accepted US purity of 583 parts per 1000.

 

750
18K gold is marked 750, being 750 parts gold per 1000.

 

925
Sterling silver 925, meaning 925 parts silver per 1000.

ACROITE
Acroite is a rare, colorless variety of tourmaline.

 

Adamantine
the term used to describe a gemstone with a brilliant luster like that of a diamond.

 

Adularia
Adularia is a common type of moonstone, a whitish-bluish semi-translucent stone. Adularia is usually set as a cabochon. Adularia was very popular early in the 20th century and was extensively used in Art Nouveau jewelry. Adularia has a hardness of 6 and a specific gravity of 2.57.

 

Agate
Agate is a variety of chalcedony (a family of microcrystalline quartz). Agate is a very common stone that is often used in jewelry. It is found in a wide range of colors, including black, gray, brown, reddish, green, pink, blue, and yellow. Agate can be flecked with color and is often banded, exhibiting layers of quartz. Agate is porous and takes dye easily, it is frequently dyed to enhance the coloration and the banding. White agate was used often in Victorian jewelry, mostly as a background. Moss agate has green, red or black dendritic inclusions. Onyx is agate whose bands are parallel. Eye agate has banding arranged in concentric circles. Agate has a hardness of 6.5 to 7 and a specific gravity of 2.6. The agate pin above is from Miracle.

 

Alexandrite
Alexandrite is a variety of chrysoberyl named after Czar Alexander II, it is a color change stone that is green in daylight and light red in artificial light. Mined in Russia, Brazil, Burma, Ceylon, and Rhodesia. Laboratory produced alexandrite is common, and it is often sold as natural alexandrite. Alexandrite has a hardness of 8.5 and a specific gravity of 3.64-3.74.

 

Alexandrite Effect
the “Alexandrite Effect” is a phenomenon in which a stone appears to be different colors depending upon the type of light it is viewed in. For example, the stone alexandrite appears to be red when seen in candle light and blue to green when seen in fluorescent light. Many other stones exhibit the “Alexandrite Effect,” including garnet and sapphire.

 

Alloy
An alloy is the homogeneous mixture or solid solution of two or more metallic elements or metallic and nonmetallic elements. The alloy is usually achieved by bringing the metals to a molten state under high temperatures and fusing or dissolving them into one solid solution. In jewelry, combining different metals is commonly done to augment the color, hardness and/or luster of the resulting alloy.
Some common alloys used in jewelry manufacture:
Common gold alloys are made by mixing gold, silver, copper, and/or other metals to produce 14K, 18K and 22K gold, white gold (gold and nickel or palladium), rose gold (gold and copper), green gold (gold with silver or silver and cadmium) , and blue gold (a recent gold color perfected by only a few jewelers).
Sterling silver is a combination of 92.5% silver and 7.5% copper, while coin silver is 80% silver and 20% copper.
Brass is an alloy typically of 60% copper and 40% zinc.
Bronze is an alloy of at least 60% copper and tin or other metals.
Pewter is an alloy of low melting point metals including tin, lead, antimony, bismuth and sometimes a bit of silver or copper. U.S. manufacturers are required by law to make lead free pewter.
Niello is a black alloy of silver, copper, lead and sulphur. It is used to fill engraving, imparting an inlaid effect after the metal is fired and polished.
Nickel silver (also called German silver) is a white metal alloy of 70% copper, 20% zinc and 10% nickel. It contains no silver. Many people are allergic to nickel and because of this, the use of nickel silver in jewelry has been outlawed in some countries.

 

Almandine
A violet-tinged variety of garnet that ranges from a deep rich red to purplish red to orange reddish-brown color. The most valuable stones contain less orange and brown. There are many varieties of garnet, but almandine is the most common. The star garnet which exhibits asterism is an almandine.

Alpaca
Alpaca (also spelled alpacca) is an alloy consisting of mostly copper (roughly 60 percent), and approximately 20 percent nickel, about 20 percent zinc, and about 5 percent tin. This metal is a silver substitute

 

Aluminum
Aluminum is a lightweight, silver-white metal. When aluminum was first discovered in the 18th century, it was more valuable than gold. Now inexpensive, aluminum is used in many alloys. Some inexpensive jewelry was made using aluminum.

 

Amazonite
Amazonite is a gem variety of microcline feldspar. It displays a schiller of light which is caused by inclusions. Amazonite varies from bright verdigris green to a bluish green and is mined in the United States, Brazil, Zimbabwe, Russia, Australia and Namibia.
Amazonite has a hardness of 6 and a specific gravity of 2.56-2.58. Most Amazonite is opaque, but rare crystals are transparent.

 

Amber
Amber is a fossilized resin from pine trees. Amber deposits have been found that are over 150 million years old, but most amber used in jewelry or ornamentals is between 20-90 million years old. As the sticky resin rough amberoozed from ancient pine trees, small insects, plant material, feathers and other small objects in the path of the flow became entrapped. Over time, the resin was encased in dirt and debris and through a process of heat and pressure it fossilized to become amber. Amber exhibits a resinous luster. Also see reconstituted amber and inclusions.
Amber has a hardness of 2.5 and a specific gravity of 1.05-1.10.

 

American Ruby
The term “American ruby” is actually a pyrope garnet (and not a ruby at all). There are real rubies found in the US, but they are not referred to as “American rubies.”

 

Amethyst
Amethyst is the purple variety of quartz. Although it must always be purple to be amethyst, it can and does have a wide range of purple shades including purple, lilac and mauve. The most expensive amethyst is a deep purple but today most amethyst is heat treated to produce a deeper color.
Amethyst is found in geodes and alluvial deposits all over the world and occurs in both crystalline or messi ametrine forms. It is a 7 on the Mohs scale of hardness.

 

Ametrine
This is a bi-color variety of quartz containing both amethyst and citrine colors. The stone is usually cut in facets in a rectangular shape to show both the yellow and purple colors. The Anahi Mine in Bolivia is the major source for ametrine.

 

Ammolite
Ammolite is the mineralized, fossilized and opalized remains of an ammonite shell which was exposed to tectonic pressure, mineralization, and intense heat.

 

Ammonite
Sea faring creatures from the Cretaceous period, ammonites were mollusks that built a chambered shell in which they would pump air into the empty chambers which allowed them to float at different levels of the ocean.

 

Amulet
A small object usually worn around the neck or as a ring to ward off evil, harm, or illness. May also be worn to bring good fortune and protection from harm. A charm, fetish or good-luck piece.
Some common amulets:
The scarab amulet was sacred to the Egyptians and symbolized rebirth. The Ankh is an Egyptian amulet which symbolized eternal life. It is thought to be the oldest and most sacred Egyptian amulet. The Eye of Horus amulet was believed to protect the wearer from evil in life and in the afterlife. Also see talisman.

 

Ankh
An ancient Egyptian hieroglyphic representing life, or the power to give life. A symbol that looks like a cross with a loop at the top, many Egyptian artifacts depict the gods holding an Ankh.

 

Anneal
Metal is annealed by heating to make it workable. In the making of jewelry, precious metals become work hardened or stressed when they are hammered, forged, rolled or bent (as in fold forming) making it brittle. Jewelers sometime purchase metals in their annealed state which may be referred to as soft or half hard. Different metals become annealed at different temperatures and jewelers look for the “color” to determine when the metal has reached its annealed state. These colors are described as bright orange, dull red and cherry red.

 

Asterism
A luminous star like effect exhibited in some gemstones like star sapphires, garnets and rubies. Asterism is caused by inclusions of tiny, parallel, rutile needles and may result in four, six or even twelve rayed stars. (Pronounced: as-ter-iz-mm)

 

Aventurescence
The effect caused by small inclusions of minerals like mica, hematite, pyrite, or goethite which cause a gemstone to exhibit a glistening or sparkling effect when rotated or moved. The name is derived from aventurine, a green variety of quartz. (Pronounced: ah-ven-shur-ess-ense)

 

Aventurine
Cabochon Aventurine is a translucent to opaque variety of microcrystalline quartz. Small inclusions of shiny minerals give the stone a sparkling effect known as aventurescence. Aventurine ranges in color from green, peach, brown, blue and a creamy green. Mohs hardness is 6.5. (Pronounced: ah-ven-shur-ine)

 

Azurite
Azurite is a copper-based mineral that ranges in color from very deep blue to pale blue. An azurite-malachite relatively soft mineral, azurite has a hardness of 3.5 to 4. Azurite is found in many areas of the world including: Australia, the southwestern USA, France, Mexico, Morocco, Namibia, Zaire, and Europe.
Malachite, which is another copper-based mineral, is often found with azurite. When found together it is called Azurite-Malachite.

Baddeleyite
A mineral with the same chemical composition as cubic zirconia. It is powdered, melted down, and mixed with oxides to make cubic zirconia.

Baffa diamond
Baffa diamond is actually rock crystal and not a real diamond.

Baguette
A gemstone cut in a narrow rectangular shape reminiscent of a loaf of French bread, from which it draws its name. Small diamonds cut this way are often used as accents for rings and necklaces.

Bail
A hoop-like attachment for a pendant that allows a pendant to be worn on a chain or necklace. Some pins or brooches are supplied with removable bails. These are usually made by soldering a hoop to a small tube which can then be slipped over the pin stem so the piece can also be worn as a necklace on a chain, collar or omega necklace.

Bakelite
A moldable plastic invented by Leo Bakeland in 1909, it was used in jewelry extensively during the U.S. great depression of the 1930’s. Bakelite can be molded, lathe-carved, and one color can be inlaid into another, as in polka dots. The inlaid and carved pieces are especially popular with collectors today. It has a distinct scent when rubbed similar to formaldehyde.

Bale
See Bail.

Band
A ring, (such as a traditional wedding band), that has the same width all the way around.

Banded agate
Banded agate is a type of agate with distinct layers of color.

Bangle
A bangle is a stiff bracelet. Some bangles have a hinge; others are solid and must be slipped over the hand.

Bar and Ring Clasp
A bar and ring clasp (also called a toggle clasp) is a jewelry fastener in which a bar can be inserted into a ring to fasten a piece of jewelry. It is used to attach the two ends of a necklace or bracelet.

Bar Brooch
A bar shaped, (long, narrow), brooch which is often set with gemstones or pearls.

Bar closure
A hinged bar which fits into a catch and is secured in the catch with a pin.

Baroda Gem
‘Baroda Gem’ is a trade name for a colorless glass stone with a foil back.

Baroque
A pearl with an uneven or craggy shape and/or surface. Also an irregularly shaped stone or glass bead.

Baroque pearls
Baroque pearls are irregularly-shaped pearls. Baroque pearls can be natural or artificial.

Bar Pin
A bar pin (also called a bar brooch) is a long pin that is worn horizontally.

Barrel clasp
A method of securing two ends of a chain together by having one half of a fitting screw into the other half. When the two halves are screwed together they resemble a barrel.

Barrette
A barrette is an ornament worn clipped into the hair.

Basalt
A dark volcanic rock, often with a glassy appearance, composed chiefly of plagioclase, pyroxene, and olivine.

Base Metal
The collective term for any and all non-precious metals.

Basket
A fancy setting with a lacy or basket-looking appearance due to numerous holes pierced in the side.

Basse-taille
Basse-taille (meaning “low cutting” in French) is an enameling technique in which the underlying metal (usually gold or silver) is carved in low relief (the metal’s surface is cut away by engraving or chasing, producing a sculpted surface). The highest point of the relief carving is below the surface of the surrounding metal. Translucent enamels are applied over the carved metal, allowing the design to remain visible through the enamel. The hue of the enamel changes with the depth of the glaze, resulting in subtle variations in color over the high and low design elements.

Baton
A baton is a stone that is cut in a long, thin rectangular shape. A baton is larger than a baguette.

Bauxite
A clay-like mineral, bauxite is the principal ore of aluminum. It is composed of aluminum oxides and aluminum hydroxides. Bauxite is used as an abrasive, a catalyst, and a refractory for the lining of furnaces which are exposed to intense heat.

Bayadère
A bayadère is a pearl necklace that has many strands of pearls twisted together.

Beach Glass
Beach glass (also called sea glass) is glass from old broken bottles, windows of wrecked ships, etc. that has been worn down and etched by the sea and sand over the years. This glass is smooth and looks like beautifully sand-blasted glass and has a beautiful patina. Pieces of this glass are collected on beaches and often made into jewelry items. Brown, deep green and clear are the most common colors of sea glass; after these come blue, amber and aqua. Rare colors include pink, red, purple, light yellow, and sea green.

Bead
A small, usually round, object with a hole pierced through it to be strung as a necklace, bracelet, etc. Beads are commonly made from stone, shell, glass, or plastic.

Bell Cap
A bell cap is a jewelry finding that is used to convert a hole-less bead or stone with into a pendant. A bell cap is glued onto the bead or stone and had a loop for attaching to the piece of jewelry.

Belle Epoque
The Belle Epoque (meaning “Beautiful Time” in French) was the Edwardian period, the time of the reign of Edward VII of England (1901-1910).

Belly Ring
A form of body jewelry worn in or on the belly button.

Benitoite
Benitoite is a rare, blue gemstone that is found mostly in the San Benito River in San Benito County, near Coalinga, California (lesser quality benitoite is found in Mont St. Hilaire, Quebec, Canada). Benito means “blessed” in Spanish. This gemstones is strongy dichroic; although Benitoite is blue when viewed from most directions, it appears colorless when viewed in a single direction (the c-axis). Some unusual Benitoite is blue, but pink or orange when viewed through the c-axis. Benitoite is BaTiSi3O9 (Barium Titanium Silicate); no one is sure what element causes the blue color of benitoite, but it may be iron. Benitoite has a hardness of 6 – 6.5, a specific gravity of 3.68, and a refractive index of 1.757 – 1.804. Benitoite has a very unusual crystalline shape – it is the only known ditrigonal-dipyramidal crystal. Large stones (over 1 or 2 carats) are exceedingly rare. Benitoite was discovered in California in 1907, either by Mr. Hawkins and T. Edwin Sanders or James Marshall Couch (the story is in dispute). Heat-treated benitoite becomes orange; these stones are more expensive. Benitoite is California’s official state gemstone (since 1985).

Beryl
Beryls are a family of gemstone that include emerald, aquamarine, beryl (green), red (red beryl), morganite (pink), and heliodor (greenish yellow, named for the sun), and goshenite (colorless). Beryl has a hardness of 7 – 8, a specific gravity of 2.6 – 2.9, and the chemical formula Be3Al2SiO6. Internal flaws in beryl gems can be hidden by treating the stone with oil (this is often not disclosed to the buyer).

Beryllium
Another name for Glucinum.

Betrothal Ring
A tradition dating back to as early as ancient Rome where it was called an anulus pronubus, a betrothal ring is usually a plain ring without a stone presented by a man to his fiancée indicating their intention to marry.

Beveled
Any surface that is cut at an angle less than 90 degrees.

Bezel
Although it is now often used to refer to the entire ring setting, the bezel is more accurately the term for the metal case which the gem is set into. The ring of metal that surrounds the stone is called the “collet”.

Bezel Set
A bezel setting is a technique of setting a stone in jewelry. The stone is held in place by first soldering the bezel, or metal ring, to the base of the piece. Next, the stone is inserted and the metal is compressed tightly around the stone.

Bib Necklace
A bib necklace (also known as a collarette) is a short necklace with flowing ornaments in the front.

Birefringence
Birefringence is another name for double refraction. In doubly-refractive stones, the light entering the stone is split into two light rays, and the rays travel in different paths. These stones have more than one refractive index. Calcite, peridot, zircon, tourmaline, and titanite are doubly-refractive stones.

Birthstone
Birthstones have their roots in ancient astrology, and there have been many birthstone lists used over the years. The most common one today is based on a list first publicized by the Jewelers of America in the 1950s:
January – Garnet
February – Amethyst
March – Aquamarine
April – Diamond
May – Emerald
June – Pearl or Moonstone
July – Ruby
August – Peridot
September – Sapphire
October – Opal
November – Citrine
December – Turquoise (or Blue Topaz)

Biwa pearls
Biwa pearls are freshwater pearls from Lake Biwa in Japan. These irregularly-shaped pearls are smoother and more lustrous than most other freshwater pearls.

Black Hills Gold
A style of jewelry made in the Black Hills area of South Dakota featuring 10kt yellow gold with accents of 12kt rose and green golds usually featuring a grape and grape-leaf motif.

Black opals
Black opals are a valuable type of precious opals with a dark ground color. They are luminous, iridescent, and frequently have inclusions of many colors (“fire”). Opal is a mineral composed of silica (and some water) and is a species of quartz. The rainbow-like iridescence is caused by tiny crystals of cristobalite. Many opals have a high water content – they can dry out and crack if they are not cared for well (opals should be stored in damp cotton wool). Opals have a hardness of 5.5 to 6.5 and a specific gravity of 1.98-2.50. Black opals are found in Australia.

Black Onyx
Opaque black colored onyx.

Black pearls
Black pearls (also called Tahitian pearls) are dark-colored pearls. They are produced by the large, black-lipped pearl oyster Pinctada margaritifera (also called the Tahitian black pearl oyster), a mollusk found in the tropical Indo-Pacific Ocean. Black pearls come in many colors, including many body shades and overtone tints including gray (light gray to almost black), peacock green (especially valuable), aubergine (eggplant), and deep brown. The color of the dark nacre is determined by the minerals in the oyster’s diet (plankton) and in its environment. Many “black pearls” are dyed or irridiated to enhance or change their color; it is difficult to tell a natural pearl from a treated pearl. Tahitian pearls are graded on six factors: 1.Shape (round is most valued), 2.Size (the larger the better), 3.Surface Quality= (clean is superior to blemished), 4.Luster (the more high-gloss luster the better), 5.Nacre Thickness (thicker is better and longer lasting), and 6.Color (overtones atop the body color add value to the pearl. The most sought-after color is peacock green and darker colors are more valuable Overtone colors include blue, pink, gold, silver, aubergine, and peacock green).

Black Prince’s Ruby
Not an actual ruby, but a ruby-red color of spinel.

Black Star Diopside (Black Star Of India)
Black star of India is another name for Black Star diopside (CaMgSi2O6), an opaque black gem with a white, four-rayed star (an asterism). It has a hardness of 5.5 and a specific gravity of 3.3 – 3.6. These stones are found mostly in India. Stones are generally cut cabochon and are not enhanced.

Bleaching
Bleaching is a process in which a gemstone’s color is removed using a bleaching agent.

Blemish
A flaw, such as a nick or scratch, on the surface of a stone.

Bling bling
Bling bling is an American slang term used to describe large, showy jewelry, especially jewelry encrusted with diamonds. The term was coined in the late 1990s by the New Orleans rappers Cash Money Millionaires.

Blister Pearl
A pearl that forms attached to the shell.

Bloodstone
Bloodstone is a soft green jasper mottled with red spots from iron oxide. A type of chalcedony it is also known as Heliotrope. Bloodstone is a relatively soft stone and is one of the ancient birthstones for February or March

Bloomed Gold
The term used for gold jewelry that has been immersed in an acid bath giving it a textured, slightly matte appearance.

Blue diamonds
Blue diamonds are rare, fancy diamonds and are quite valuable. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 – 2.419.

Blue gold
Blue gold is gold with a bluish tinge. It has been alloyed with a mix that includes iron.

Blue Lace Agate
A translucent light blue agate with milky white banding.

Blue Topaz
A topaz that is light brown or colorless when mined but turns a vivid blue when exposed to heat. Blue Topaz is an alternate birthstone for December.

Bodkin
A bodkin is a heavily jeweled, Renaissance era hairpin.

Body Jewelry
Jewelry designed to be worn on or in any part of the body. While all jewelry is technically worn on the body, the term “Body Jewelry” is typically used when referring to belly rings, nose studs, toe rings, tongue bars, and for jewelry designed for pierced lips, eyebrows, nipples, or any skin surface.

Bog-oak
Bog-oak is old oak wood that has been blackened and preserved by being in low-oxygen Irish and Scotish peat-bogs for thousands of years. Bog-oak was carved and used as inexpensive Victorian era jewelry. It was also used for decorative objects, bowls, chests, dagger handles, and other decorative items.

Bohemain Diamond
A “Bohemian diamond” is not a diamond at all, it is actually a rock crystal.

Bohemian Garnet
Term for the red pyrope garnet found in much Victorian and turn of the century jewelry.

Bohemain Ruby
A Bohemian ruby is actually a pyrope garnet (and not a ruby at all).

Boke
Boke is a Japanese term for coral that is rose colored.

Bolo
A braided leather loop worn about the neck and adorned with a slide, (an ornament of silver, stone or other material fastened so that it slides up under the chin), leaving the two leather ends hanging.

Bolt Ring
A bolt ring (also known as a spring ring) is a hollow circular metal fastening ring with a spring opening. It is used to attach two other rings or links of a necklace or bracelet. The bolt ring was invented early in the 1900’s. Jewelry made prior to 1900 or so will not

Bombé
The word itself simply means “curving or bulging outward”. In regards to jewelry it refers to a dome-shaped setting often seen in rings and earrings from the 1940s and 1950s.

Bonding
Bonding is a process in which a colorless bonding agent (like plastic) is applied on and into a porous gemstone to make the stone more durable and give it an enhanced appearance.

Bone
Bone is animal bone, carved to make beads, pins, bangles, etc. It superficially resembles ivory, but has a less-complex characteristic internal patterns and a yellower color.

Book Chain
A Victorian style of chain made in gold, gold filled , and sterling silver, in which each link is a rectangular, folded piece of metal resembling a book. They were often elaborately engraved and had large lockets attached.

Boron
A soft, brown, nonmetallic element. It is extracted with some difficulty and in its reduced state appears as a substance of a deep olive color, in a semi-metallic form, and in colorless quadratic crystals similar to the diamond in hardness and other properties. Boron is used in flares, propellant mixtures, nuclear reactor control elements, abrasives, and hard metallic alloys.

Bort
Bort is a term for industrial grade diamonds.

Botanical Gems
Botanical gems are minerals that form from plants or plant material. Some botanical gems include amber (fossilized tree resin), coconut pearl (a rare, shiny, calcareous, pearl-like mineral that forms inside the coconut, Cocos nucifera), and pearl opal (also called Tabasheer opal, which form in injured bamboo joints).

Boulder Opal
Boulder opal forms on a dark ironstone base (the host rock) and occurs as a thin uneven layer adhering to the ironstone. Because of the uneven layers, sometimes part of the ironstone is visible on the surface of the stone.
Boulder opal is found in a wide range of colors including: green, blue, aqua, and pink. See opal varieties and opal description for more in depth discussions about this wonderful gemstone.

Bouton Pearl
A bouton pearl (also called a blister pearl) is a pearl that developed attached to the inside of the mollusk’s shell. This type of pearl must be cut off the shell, and is therefore hemispherical (half a sphere). Because of their shape, blister pearls are mostly used for earrings.

Bow
Bows are a common motiff in jewelry. The pin pictured above is a sterling bow made by Trifari.

Bow-Guard
Originally just a wide leather strap worn on the left wrist to protect the arm from bow strings, it is now usually decorated with a wide ornament of silver.

Box Clasp
A method of connecting two ends of a chain. One end has a box with an opening which is notched on the top of the box. The other end has a flat piece of metal which has been folded over to form a spring with a knob at the end. The folded metal spring slips into the hole in the box with the knob sticking out through the notch in the top. The compressed spring holds the two ends in place. It is released by pressing the knob. The connection is usually reinforced by a figure 8 catch.

Box-and-tongue clasp
See Box Clasp.

Box Chain
A chain in which each link is wide and square so that it resembles a box.

Bracelet
A form of jewelry worn around the wrist.

Braganza
The Braganza is a huge gemstone that may or may not be a diamond. This Portuguese stone is said to weigh 1680 carats (which would make it the largest-known diamond), but it has not been authenticated – it may actually be a clear topaz.

Brass
An alloy made up of roughly half copper and half zinc which has a nice yellow color.

Brazilian chain
A Brazilian chain (also called a snake chain) is a metal chain made up of a series of small, linked cups.

Brilliant cut
Brilliant cut stones have 56 facets, 32 facets are above the girdle, 24 are below. Most modern-day diamonds are brilliant cut since it maximizes the amount of reflected light from the stone (its natural fire). The brilliant cut was introduced in the 1600’s, possibly by Cardinal Mazarin (1602-1661), a politician and lover of gems.

Brecciated
Rock composed of sharp-angled fragments embedded in a fine-grained matrix. Some Jaspers and agates are brecciated (pronounced: bretch-e-ated).

Bridal set
An engagement and wedding ring that come in a set and usually match or compliment each other.

Bridge jewelry
Bridge jewelry is jewelry that “bridges the gap” between fine (precious) jewelry and costume jewelry. An example of bridge jewelry is sterling silver pieces.

Brilliance
The amount of sparkle a stone gives off through reflection and refraction of light.

Brilliant-cut
A cut gemstone having 56 to 58 facets to maximize the volume of light that is reflected from the inside and thus produce the greatest brilliance. The most common shape of brilliant cut stones are round, which is why this is type of cut is sometimes called a “round-cut”, but oval, marquise, pear shape and heart shapes are not unusual.

Briolette
A gemstone cut with triangular facets into the shape of a teardrop or elongated pendant.

Britannia Or Pewter
An alloy of tin, antimony, and copper with a dull silver-color.

Britannia Silver
A silver alloy composed of 958 parts silver in 1000 hallmarked with the figure of Britannia. Britannia silver was mandatory in England from 1697 to 1720 to prevent the melting down of sterling coins to create silver objects.

Broker
See Agent.

Bronze
A very dense and heavy alloy of 60% copper and 40% tin. It has a dull brown color and is not favored for jewelry because of the weight.

Brooch
An ornamental piece of jewelry with a pin and clasp to be attached to clothing, from the French word “broche”, meaning “to pierce” or an object/weapon made for piercing.

Bruiting
The term for shaping the girdle of a diamond, the first step in the cutting process.

Brushed Finish
A series of tiny parallel lines scratched onto a surface with a wire brush or polishing tool to produce texture

Bruting
Bruting is the first step in cutting a diamond. Bruting involves shaping the girdle, which gives the stone its basic shape.

Bubbles
Bubbles are spherical or tear-shaped bubbles of gas captured in glass stones. Bubbles can also be found in resins (like plastics and amber), and much less-frequently in minerals (like quartz, emerald, and topaz). Looking for bubbles is one way to determine if a gem is glass or a gemstone.

Bud Leaf
The slang term given to the leaf of the cannabis plant, which is the plant used to make hemp products. It is a popular motif in modern jewelry. Also called a “marijuana leaf”.

Buffalo Stone
See Ammolite.

Bugle Bead
A bugle bead is a long, thin, tube-shaped glass bead.

Bulla
A bulla is an ancient Roman pendant that consists of a rounded container holding an amulet (a good luck charm). The bulla is worn on a strap around the neck.

Burnish setting
A setting in which the gem is set flush with the setting’s surface without using prongs to hold it in place.

Buttercup setting
A deep six prong setting with prongs that flare from the scalloped looking base resembling a buttercup flower.

Butterfly Chain
A chain composed of very tiny butterfly-shaped links with oval-shaped “wings”. The butterflies are linked head to tail at a slight angle very close to one another so that the wings form a long continuous spiral along the length of the chain.

Butterfly clutch
A fitting that slides onto the back of an earring post to secure it in place.

Butterfly wing
Butterfly wing jewelry is made from real butterfly wings. A picture is usually painted on the wings, which is then enclosed in glass or plastic and then mounted in metal to make a pin, pendant, or other piece of jewelry.

Button
A method of joining two parts of a garment together by means of a toggle fastened to one side of the garment which is then pushed through a slit in the other side of the garment. The toggle, called a “button”, is usually a disk and may be quite ornamental. Some buttons are worn strictly as decoration rather than serving a functional purpose. The term “button” is also applied to round pins that usually bear a slogan of some kind.

Button Earring
An earring with no dangling parts.

Byzantine Chain
An intricately designed chain. Two pairs of oval-shaped links are linked together. Each pair is then parted to allow a large thick oval link to be attached to the other pair.

“C” catch
The most common means of securing a brooch before 1900 or so when “safety catches” were invented. The pin connected to one side of the brooch is threaded through a layer of the garment and rests in a “C” shaped catch on the other side of the brooch. The “C” had no mechanism to hold the pin in place and so the pins were usually designed to be long enough to extend far enough beyond the end of the brooch to weave back into the garment for security.

C-OX
A green cubic zirconia (CZ) stone.

Cable Chain
A chain made of round linked rings of uniform size. This tends to be what most people think of when they think of the word “chain”. It is the same style of chain as the cable used to anchor large ships to a dock.

Cabochon
From the French “caboche”, meaning “knob/small dome”, a cabochon is a stone cut into the shape of a small dome in a round, oval, rectangle, triangle, or teardrop shape without any facets. This style is commonly used with opaque to translucent stones such as opal, moonstone, jade and turquoise. Some transparent stones such as emeralds, amethyst and garnet, are also sometimes fashioned as cabochons. An almandine (garnet) cabochon is called a “carbuncle”.

Cairngorm
Cairngorm is a yellow-brown type of smoky quartz that is often used in traditional Celtic jewelry. Cairngorm is not Scottish topaz. The supply of cairngorm is virtually exhausted, so heat-treated Brazilian amethyst is used as a substitute in Scottish jewelry.

Calcium
A silvery-white, moderately hard metallic element which is the fifth most abundant element comprising approximately 3% of the earth’s crust, and is a basic component of most animals and plants. It burns with a brilliant light and occurs naturally in limestone, gypsum, and fluorite.

Calcite
Calcite (Calcium Carbonate, CaCO3) is a very common mineral that comes in a wide variety of forms, shapes and colors. The trigonal crystals range from translucent to transparent. Transparent calcite exhibits a double refraction effect (when you look through the crystal, singel items are doubled). Calcite has a hardness of 3 (most forms), a specific gravity of about 2.7, a refractive index of 1.49 and 1.66, and a white streak.

Calibrated
A calibrated stone is one that has been cut exactly to a standard size, i.e. 5 mm, 10 mm x 14 mm. Jewelers often purchase calibrated cabochons or faceted stones when the design requires two or more stones of the same exact size or when a design will be duplicated many times as in manufactured jewelry.

Calibré Cut
Small stones cut in an oblong shape and set close together.

California ruby
A California ruby is actually a pyrope garnet (and not a ruby at all).

Calsilica
Rainbow calsilica is a newly-found, multi-colored, layered stone composed of calcium and silica. This stone has been recently used for Zuni fetish carvings and in some jewelry (beads and cabochon cut stones). Rainbow calsilica was only recently found in Mexico or Northern South America (it’s origin remains mysterious). Some people theorize that this stone formed as a result of the runoff of mining or oil-drilling chemicals, and has only formed in the last 30 to 50 years (but this is uncertain).

Cameo
A type of jewelry in which the stone around a design is cut away leaving the design in relief, typically against a contrasting background. Cameos are often made of shell and coral, although hard stone cameos such as agate, onyx, and sardonyx are more valuable. Cameos have been carved from the Hellenistic period, and ancient motifs such as the goddess Athena or a Baccante, (follower of Bacchus), were popular cameo subjects in Victorian times through the 1930’s. The opposite of a cameo is called “Intaglio”.

Cameo habille
A cameo habille (meaning “dressed cameo” in French) is a “jewel within a jewel,” a cameo in which the subject carved in the cameo (usually a woman) is wearing a miniature piece of jewelry (like a tiny diamond necklace with a stone embedded in the cameo).

Camphor glass
Camphor glass is cloudy white glass that is either blown or pressed. Camphor glass was very popular in the mid-nineteenth century and used for jewelry, candlesticks, vases, dishes, barometers, and other pieces. Camphor glass jewelry imitates rock crystal.

Canary diamonds
Canary diamonds are diamonds that have a deep yellow color. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 – 2.419.

Cannetille
A wirework decoration which uses coiled and twisted gold wire to achieve a delicate scrolling effect.

Cape Amethyst
A form of Amethyst layered or striped with milky quartz.

Cape Ruby
A Cape ruby is actually a pyrope garnet (and not a ruby at all).

Carat
One of the 4 C’s of diamond grading. Abbreviated “ct.” and spelled with a “c” is a measure of weight used for gemstones, (as opposed to karat with a “K”, which is a measure of the purity of a gold alloy). One carat is equal to 1/5 of a gram (200 milligrams). Stones are measured to the nearest hundredth of a carat. A hundredth of a carat is also called a point. Thus a .10 carat stone can be called either 10 points, or 1/10 of a carat. Small stones like .05, and .10ct are most often referred to by point designations. A one carat round diamond of average proportions is approximately 6.5mm in diameter. Note that this relationship of weight and size is different for each family of stones. For example ruby and sapphire are both heavier than diamond (technically, they have a higher specific gravity, so a 1 carat ruby or sapphire is smaller in size than a one carat diamond.)

Carbon
A non-metallic element that occurs in all organic compounds and many inorganic compounds. Carbon is combustible and has the interesting ability to bond with itself, as well as with many other elements.

Carbonado
A carbonardo is a rare type of opaque black diamond; they are not used for jewels, but for items like drilling bits and abrasive wheels. They were once thought to have been formed as a result of a comet impact 2 billion years ago, but this is no longer thought to be true. The largest diamond ever found was a carbonardo that weighed over half a kilogram. Carbonadoes are found in Bahia, Brazil, South America. Unlike other diamonds, carbonadoes are not found in a crystallized form – they are found in irregular or rounded fragments. Carbonadoes have a hardness of 10 and a specific gravity (density) of 3.1-3.3. Diamonds have a very hard polycrystalline carbon structure.

Carbon Spots
Diamonds are carbon that has been compressed over time. Carbon spots are a kind of flaw, or “inclusion”, found in diamonds showing as black spots inside the clear diamond.

Carbonate
A substance treated with carbon dioxide, such as limestone.

Carbuncle
An almandine (garnet) cabochon.

Carnelian
A translucent red or orange variety of chalcedony, sometimes banded red and orange like an agate. Once believed to benefit the wearer’s health and love life. Most carnelian comes from Brazil, India, Siberia, and Germany.

Casting
A means of reproducing an object by making a mold of it and pouring metal, plaster, or some other material that sets over time into the mold. See Centrifugal casting, Electrotype, Lost wax process, and sand casting.

Catalin
See Bakelite.

Cathedral Setting
A cathedral ring setting is a simple band that arches when seen from the side (like the arches of a cathedral).

Cat’s eye
Cat’s eye (chatoyant chrysoberyl) is a yellow to green-yellow to gray-green stone with a bright, pupil-like slit that seems to move slightly as the stone is moved. Most Cat’s eye is cut as cabochons to maximize the distinctive pupil-like effect. Most cat’s eye chrysoberyl is found in Brazil. Cat’s eye chrysoberyl has a hardness of 8.5. This stone is sometimes enhanced by irradiation (this process improves the color and accentuates the stone’s asterism).

CE
Common Era, or in the Christian calendar, AD, anno domini, meaning “in the year of our Lord”.

Cell Enameling
See Cloisonné.

Celluloid
A plastic derived from cellulose, a natural plant fiber, first synthesized around 1870 as a synthetic ivory. It can be cut, rolled, folded, perforated, ironed, turned, or embossed when heated, but cannot be injected. Celluloid is flammable and deteriorates easily if exposed to moisture. jewelry made of celluloid was often set with rhinestones. Hair combs and other dresser articles are still often made of celluloid today. Also called French ivory, Ivoride, Ivorine, Ivorite, and Pyralin

Celtic jewelry
Celtic jewelry was made by the Celts in Ireland, Wales, Scotland, and Brittany. The Celts used bronze, silver and gold in their jewelry and stones like cairngorm and amethyst. Circular brooches with a long, hinged pin, called penannular brooches, date from ancient times. The earliest-known piece of Celtic jewelry is the Hunterston brooch from A.D. 700

Celtic Revival
Jewelry made during the mid-nineteenth century reflective of the styles of jewelry used in early Ireland based on archaeological artifacts.

Center Stone
Usually a diamond, (or other gemstone), that is the prominent center piece in a ring setting.

Centrifugal Casting
A method of casting jewelry in which molds are attached to the outside edge of hollow tube. Metal is poured into the tube and as the tube is spun at high speed centrifugal force pulls the molten metal into the molds.

Certification
A grading report given to a precious stone by a reputable and recognized laboratory that defines the physical characteristics and quality rating of a gem. See Assay and IGI

CFW
CFW is an abbreviation for cultured freshwater pearls.

Chain
A strand of linked loops, rings, or beads used for bracelets or necklaces. Popular types of chain include: Book chain, Box, Butterfly, Byzantine, Cable, Cuban, Curb, Figaro, Figogucci, Foxtail, Herringbone, Marina, Mariner, Mesh, Omega, Panther link, Rolo, Rope, San Marco, Serpentine, Singapore, and Snake. (See individual listings.)

Chalcedony
A family of colored quartz stones including agate, onyx, carnelian, cat’s eye, and jasper that commonly have a milky or waxlike luster. When chalcedony is variegated with with spots or figures, or arranged in differently colored layers, it is called agate; and if by reason of the thickness, color, and arrangement of the layers it is suitable for being carved into cameos, it is called onyx.

Champagne Diamond
A champagne diamond is a pinkish brown diamond (having a color of C2-C3). Most champagne diamonds are mined in Western Australia (in the Argyle Mine). The color is produced by a their low nitrogen content

Champlevé
A type of enameling in which powdered glass is placed in areas of a piece of jewelry that have been carved away specifically for this purpose before firing. The glass powder melts filling the carved areas with solid glass.

“C” catch
The most common means of securing a brooch before 1900 or so when “safety catches” were invented. The pin connected to one side of the brooch is threaded through a layer of the garment and rests in a “C” shaped catch on the other side of the brooch. The “C” had no mechanism to hold the pin in place and so the pins were usually designed to be long enough to extend far enough beyond the end of the brooch to weave back into the garment for security.

C-OX
A green cubic zirconia (CZ) stone.

Cable Chain
A chain made of round linked rings of uniform size. This tends to be what most people think of when they think of the word “chain”. It is the same style of chain as the cable used to anchor large ships to a dock.

Cabochon
From the French “caboche”, meaning “knob/small dome”, a cabochon is a stone cut into the shape of a small dome in a round, oval, rectangle, triangle, or teardrop shape without any facets. This style is commonly used with opaque to translucent stones such as opal, moonstone, jade and turquoise. Some transparent stones such as emeralds, amethyst and garnet, are also sometimes fashioned as cabochons. An almandine (garnet) cabochon is called a “carbuncle”.

Cairngorm
Cairngorm is a yellow-brown type of smoky quartz that is often used in traditional Celtic jewelry. Cairngorm is not Scottish topaz. The supply of cairngorm is virtually exhausted, so heat-treated Brazilian amethyst is used as a substitute in Scottish jewelry.

Calcium
A silvery-white, moderately hard metallic element which is the fifth most abundant element comprising approximately 3% of the earth’s crust, and is a basic component of most animals and plants. It burns with a brilliant light and occurs naturally in limestone, gypsum, and fluorite.

Calcite
Calcite (Calcium Carbonate, CaCO3) is a very common mineral that comes in a wide variety of forms, shapes and colors. The trigonal crystals range from translucent to transparent. Transparent calcite exhibits a double refraction effect (when you look through the crystal, singel items are doubled). Calcite has a hardness of 3 (most forms), a specific gravity of about 2.7, a refractive index of 1.49 and 1.66, and a white streak.

Calibrated
A calibrated stone is one that has been cut exactly to a standard size, i.e. 5 mm, 10 mm x 14 mm. Jewelers often purchase calibrated cabochons or faceted stones when the design requires two or more stones of the same exact size or when a design will be duplicated many times as in manufactured jewelry.

Calibré Cut
Small stones cut in an oblong shape and set close together.

California ruby
A California ruby is actually a pyrope garnet (and not a ruby at all).

Calsilica
Rainbow calsilica is a newly-found, multi-colored, layered stone composed of calcium and silica. This stone has been recently used for Zuni fetish carvings and in some jewelry (beads and cabochon cut stones). Rainbow calsilica was only recently found in Mexico or Northern South America (it’s origin remains mysterious). Some people theorize that this stone formed as a result of the runoff of mining or oil-drilling chemicals, and has only formed in the last 30 to 50 years (but this is uncertain).

Cameo
A type of jewelry in which the stone around a design is cut away leaving the design in relief, typically against a contrasting background. Cameos are often made of shell and coral, although hard stone cameos such as agate, onyx, and sardonyx are more valuable. Cameos have been carved from the Hellenistic period, and ancient motifs such as the goddess Athena or a Baccante, (follower of Bacchus), were popular cameo subjects in Victorian times through the 1930’s. The opposite of a cameo is called “Intaglio”.

Cameo habille
A cameo habille (meaning “dressed cameo” in French) is a “jewel within a jewel,” a cameo in which the subject carved in the cameo (usually a woman) is wearing a miniature piece of jewelry (like a tiny diamond necklace with a stone embedded in the cameo).

Camphor glass
Camphor glass is cloudy white glass that is either blown or pressed. Camphor glass was very popular in the mid-nineteenth century and used for jewelry, candlesticks, vases, dishes, barometers, and other pieces. Camphor glass jewelry imitates rock crystal.

Canary diamonds
Canary diamonds are diamonds that have a deep yellow color. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 – 2.419.

Cannetille
A wirework decoration which uses coiled and twisted gold wire to achieve a delicate scrolling effect.

Cape Amethyst
A form of Amethyst layered or striped with milky quartz.

Cape Ruby
A Cape ruby is actually a pyrope garnet (and not a ruby at all).

Carat
One of the 4 C’s of diamond grading. Abbreviated “ct.” and spelled with a “c” is a measure of weight used for gemstones, (as opposed to karat with a “K”, which is a measure of the purity of a gold alloy). One carat is equal to 1/5 of a gram (200 milligrams). Stones are measured to the nearest hundredth of a carat. A hundredth of a carat is also called a point. Thus a .10 carat stone can be called either 10 points, or 1/10 of a carat. Small stones like .05, and .10ct are most often referred to by point designations. A one carat round diamond of average proportions is approximately 6.5mm in diameter. Note that this relationship of weight and size is different for each family of stones. For example ruby and sapphire are both heavier than diamond (technically, they have a higher specific gravity, so a 1 carat ruby or sapphire is smaller in size than a one carat diamond.)

Carbon
A non-metallic element that occurs in all organic compounds and many inorganic compounds. Carbon is combustible and has the interesting ability to bond with itself, as well as with many other elements.

Carbonado
A carbonardo is a rare type of opaque black diamond; they are not used for jewels, but for items like drilling bits and abrasive wheels. They were once thought to have been formed as a result of a comet impact 2 billion years ago, but this is no longer thought to be true. The largest diamond ever found was a carbonardo that weighed over half a kilogram. Carbonadoes are found in Bahia, Brazil, South America. Unlike other diamonds, carbonadoes are not found in a crystallized form – they are found in irregular or rounded fragments. Carbonadoes have a hardness of 10 and a specific gravity (density) of 3.1-3.3. Diamonds have a very hard polycrystalline carbon structure.

Carbon Spots
Diamonds are carbon that has been compressed over time. Carbon spots are a kind of flaw, or “inclusion”, found in diamonds showing as black spots inside the clear diamond.

Carbonate
A substance treated with carbon dioxide, such as limestone.

Carbuncle
An almandine (garnet) cabochon.

Carnelian
A translucent red or orange variety of chalcedony, sometimes banded red and orange like an agate. Once believed to benefit the wearer’s health and love life. Most carnelian comes from Brazil, India, Siberia, and Germany.

Casting
A means of reproducing an object by making a mold of it and pouring metal, plaster, or some other material that sets over time into the mold. See Centrifugal casting, Electrotype, Lost wax process, and sand casting.

Catalin
See Bakelite.

Cathedral Setting
A cathedral ring setting is a simple band that arches when seen from the side (like the arches of a cathedral).

Cat’s eye
Cat’s eye (chatoyant chrysoberyl) is a yellow to green-yellow to gray-green stone with a bright, pupil-like slit that seems to move slightly as the stone is moved. Most Cat’s eye is cut as cabochons to maximize the distinctive pupil-like effect. Most cat’s eye chrysoberyl is found in Brazil. Cat’s eye chrysoberyl has a hardness of 8.5. This stone is sometimes enhanced by irradiation (this process improves the color and accentuates the stone’s asterism).

CE
Common Era, or in the Christian calendar, AD, anno domini, meaning “in the year of our Lord”.

Celebrity
Celebrity is a mark of generally low- to medium-quality costume jewelry made by a New York company. The trademark “Celebrity” is owned by the Celebrity Jewelry Company of Philadelphia, Pennnsylvania, which makes jewelry of gold and silver, with precious stones.

Cell Enameling
See Cloisonné.

Cellini, Benvenuto
Benvenuto Cellini (1500-1571) was the pre-eminent Italian jeweler during the renaissance. Cellini’s intricate works utilized beautifully-cast metals, enamel, table-cut gems, and pearls

Celluloid
A plastic derived from cellulose, a natural plant fiber, first synthesized around 1870 as a synthetic ivory. It can be cut, rolled, folded, perforated, ironed, turned, or embossed when heated, but cannot be injected. Celluloid is flammable and deteriorates easily if exposed to moisture. jewelry made of celluloid was often set with rhinestones. Hair combs and other dresser articles are still often made of celluloid today. Also called French ivory, Ivoride, Ivorine, Ivorite, and Pyralin

Celtic jewelry
Celtic jewelry was made by the Celts in Ireland, Wales, Scotland, and Brittany. The Celts used bronze, silver and gold in their jewelry and stones like cairngorm and amethyst. Circular brooches with a long, hinged pin, called penannular brooches, date from ancient times. The earliest-known piece of Celtic jewelry is the Hunterston brooch from A.D. 700

Celtic Revival
Jewelry made during the mid-nineteenth century reflective of the styles of jewelry used in early Ireland based on archaeological artifacts.

Center Stone
Usually a diamond, (or other gemstone), that is the prominent center piece in a ring setting.

Centrifugal Casting
A method of casting jewelry in which molds are attached to the outside edge of hollow tube. Metal is poured into the tube and as the tube is spun at high speed centrifugal force pulls the molten metal into the molds.

Certification
A grading report given to a precious stone by a reputable and recognized laboratory that defines the physical characteristics and quality rating of a gem. See Assay and IGI

CFW
CFW is an abbreviation for cultured freshwater pearls.

Chain
A strand of linked loops, rings, or beads used for bracelets or necklaces. Popular types of chain include: Book chain, Box, Butterfly, Byzantine, Cable, Cuban, Curb, Figaro, Figogucci, Foxtail, Herringbone, Marina, Mariner, Mesh, Omega, Panther link, Rolo, Rope, San Marco, Serpentine, Singapore, and Snake. (See individual listings.)

Chalcedony
A family of colored quartz stones including agate, onyx, carnelian, cat’s eye, and jasper that commonly have a milky or waxlike luster. When chalcedony is variegated with with spots or figures, or arranged in differently colored layers, it is called agate; and if by reason of the thickness, color, and arrangement of the layers it is suitable for being carved into cameos, it is called onyx.

Champagne Diamond
A champagne diamond is a pinkish brown diamond (having a color of C2-C3). Most champagne diamonds are mined in Western Australia (in the Argyle Mine). The color is produced by a their low nitrogen content

Champlevé
A type of enameling in which powdered glass is placed in areas of a piece of jewelry that have been carved away specifically for this purpose before firing. The glass powder melts filling the carved areas with solid glass.

Chandelier Earring
An earring with a drop suspended like a chandelier. Also called a “Drop Earring” or “Dangle Earring”.

Channel Inlay
A design similar to enameling in which stones, rather than melted plastic or glass, are cut to shape and set into the recesses of a piece of jewelry. Commonly seen with jewelry using mother of pearl and turquoise.

Channel Set
A style of setting in which a number of uniformly sized small stones, usually of the round cut, princess cut or baguette shapes, are set side by side in a grooved channel. Unlike most setting methods the stones are not secured individually with prongs and there is no metal visible between the stones.

Chaplet
A garland, wreath, or ornamented band worn around the head. Chaplets are made of metal with repoussé decoration or embellished with gemstones and pearls.

Charel
Charel is a mark of relatively rare, medium-quality costume jewelry made by the Charel Jewelry Company, Inc. of Brooklyn, New York. Many Charel pieces have pastel-colored plastic stones on plated metal.

Charm
A pendant or trinket worn on a bracelet, earring or necklace.

Charm Bracelet
A chain link bracelet with charms attached to it. (It’s not a charm bracelet until it has charms attached.)

Charm Ring
A ring with a charm attached to the ring band.

Charoite
Charoite is a fairly recent discovery found in Russia in 1978 in the Murun mountains in Yakutia, near the Charo River. This is the only known location for this rare mineral.
It ranges in color from a light lilac to a deep purple and can be mottled with gray, white and black inclusions. The chatoyant variety in a bright deep purple, is usually considered more valuable than the non-chatoyant variety although both are used in jewelry and compliment a number of other stones.

Chasing
A method of decorating the front, (or outside), of metal objects by making indentations using shaped punches and a chasing hammer. The opposite of chasing is repoussé.

Chatelaine
French for “Lady of the House”, a chatelaine is an ornamental chain or pin worn at a woman’s waist from which dangle keys, trinkets, scissors, needle cases, pencils, purse, etc. Chatelaines may be utilitarian or beautifully decorated and made from precious materials like silver.

Chatham synthetic rubies
Chatham synthetic rubies (laboratory-created rubies) were introduced by Carroll Chatham in 1959.

Chaton
A cone shaped rhinestone or crystal.

Chaton setting
A châton setting (also called coronet or arcade setting) is one in which the stone is held in by many metal claws around a metal ring.

Chatoyancy
Chatoyancy is the lustrous, cat’s eye effect seen in some cabochon stones, like cat’s eye, tiger’s eye (pictured above), and sometimes in other stones, like aquamarine. In chatoyancy, light is reflected in thin bands within the stone. Chatoyant stones are cut in cabochon to maximize the lustrous effect.

Chatoyant
A stone having a changeable luster due to the way it reflects light, such as the cat’s-eye or tiger’s eye gemstones. From the French “chatoyer”, meaning to shimmer like cats’ eyes, from the French “chat” meaning “cat”.

Chenier
Chenier is fine, hollow tubing that is used in the production of some jewelry findings (like clasps and joints), and lately, in the actual production of jewelry. The hollow tubes are lightweight and save in the use of gold. The tubes are hard to bend when they are empty, so a metal rod is inserted before bending, facilitating the bending.

Chevron setting
A chevron is a design found in heraldry resembling a shallow inverted “V”. In jewelry design, a “chevron setting” is reflective of the heraldic chevron in that it is made up of lines in a shallow inverted “V” pattern.

Chinese opal
Chinese opal is a misnomer for pearl opal (a type of organic opal), moonstone, or white chalcedony

Chloride
Any compound containing a chlorine atom.

Chlorine
An abundant element which, when isolated, appears as a poisonous, greenish-yellow gas with a disagreeable odor. It occurs naturally only as a salt, as in sea-water. Chlorine is used widely to purify water, as a disinfectant and bleaching agent, and in the manufacture of many important compounds including chloroform and carbon tetrachloride.

Choker
A close fitting necklace worn tight around the neck like a collar.

Chrome
A hard, brittle, grayish white metal, fusible with difficulty and resistant to corrosion. Its chief commercial importance is for its compounds, as potassium chromate, lead chromate, etc., which are brilliantly colored and are used dyeing and calico printing. The common modern usage is for very shiny metal objects like chrome bumpers, etc.

Chrome diopside
Chrome diopside is an emerald-green colored gemstone. It is a chromium-rich variety of the common mineral diopside (Calcium magnesium silicate). Chrome diopside has a hardness of 5 to 6 and a specific gravity of 3.3 to 3.6.

Chromium
A lustrous, hard brittle, steel-blue metallic element, resistant to corrosion and tarnishing. It is used in the hardening of steel alloys and the production of stainless steels, in corrosion-resistant decorative platings, and as a pigment in glass.

Chronograph
A chronograph is a stopwatch mechanism on a watch; it can be started, stopped and reset independently from the watch.

Chrysoberyl
A rare, hard, yellow-green mineral consisting of alumina and glucina, (beryllium aluminate), in crystal form. It is popular as a gemstone for its chatoyant qualities.

Chrysocolla
Chrysocolla (meaning “golden lime” in Greek) is an opaque blue to blue-green mineral sometimes used in jewelry. It is usually cut as a cabochon. Chrysocolla (hydrated copper silicate) is found embedded in rock crystal in copper mines in the USA, Russia, Chile, and the Congo. Although Chrysocolla has been used in ornaments since the time of the ancient Greeks, it was only described mineralogically in 1968. Its hardness varies from 2 to 4.

Chrysolite
A mineral composed of silica, magnesia, and iron sometimes used as a gem. Chrysolite ranges in color from a light pea green to a deep olive green and an oily shine. It is common in certain volcanic rocks and meteorites. Mystics have claimed that this lustrous green stone drives away evil and has special healing properties. The name chrysolite has been used in the past for yellow varieties of tourmaline and topaz.

Chrysoprase
Chrysoprase is the most valued variety of the mineral chalcedony (microcrystalline quartz) that contains nickel, giving it an apple-green color. Chrysoprase is porous and translucent. It is usually cut as a cabichon, and has been used since ancient times. Chrysoprase has a hardness of 7 and a specific gravity of 2.6. Chrysoprase is mined in Australia, Russia (the Ural Mtns.), Brazil, and the western USA. Chrysoprase is sometimes called “Australian jade,” but it is not related to jade. Hard-to-detect imitation chrysoprase is made by staining agate with chromium salts.

Cigar band
A very wide band-style ring.

Cinnabar
Cinnabar is the mineral Mercury Sulfide. Its color ranges from cinnamon to scarlet to brick red and it can be translucent to transparent. It is often carved. Cinnabar has a hardness of 2 – 2.5 (very soft) and a specific gravity of 8.1 (quite heavy).

Cinnamon stone
A brown or yellowish-brown variety of garnet more properly called “essonite”.

Cire perdu
Cire perdu (French for “lost wax”) is a process of casting metal in which the original model is sculpted in wax. The wax is entombed in clay, and the wax is then melted out, producing a hollow mold. The mold is then filled with molten metal. The clay is broken off and the cast metal remains.

Citrine
Named after the French word for lemon, “citron”. Citrine is often incorrectly called quartz topaz or citrine topaz. A variety of quartz, citrine is found in light yellow, amber-brown, and a brilliant orange that may be confused with fine imperial topaz. Most citrine comes from South America. In ancient times, citrine was revered as a gift of the sun and believed to be a powerful antidote to a viper’s venom. Citrine is the birthstone for November.

Claddagh Ring
First crafted by Master Goldsmith Richard Joyce in 1689, it is named after Claddagh, the fishing village he lived in at the time, which overlooks Galway Bay. The ring belongs to a class of rings called “Fede” or “Faith rings”, which date from Roman times and were popular in the Middle Ages throughout Europe. Whereas “Fede” rings have only two clasped hands, symbolizing faith, trust, or “plighted troth”, Claddagh rings have two hands clasping a heart, symbolizing love, surmounted by a crown, symbolizing loyalty. The ring worn on the right hand with the heart turned outward indicates that your heart is yet unoccupied. Worn on the right hand with the heart turned inward indicates that love is being considered. Worn on the left hand the with the heart turned inward shows everyone that your heart is truly spoken for.

Clarity
One of the 4 C’s of diamond grading. Gemstones with the highest clarity contain few or no inclusions (imperfections) in the stone’s crystalline structure. Clarity is graded with a 10x magnifier. The clarity rating of a diamond ranges from FL (flawless) to I (inclusions visible to the naked eye).

Clasp
A device used to connect two ends of a necklace, bracelet or watch strap. Popular types of clasps include: Barrel, box, Lobster claw, and Spring ring clasps. (See individual listings).

Class Ring
A ring that commemorates graduating from high school. It is usually engraved with the name of the school, the year of graduation, and a gem featuring one of the school’s colors.

Claw
A claw is a metal prong that holds a stone securely in a setting.

Claw Setting
A way of securing a stone in its mount using small prongs that surround it.

Cleaning Jewelry
The safest and easiest way to clean most jewelry is with a detergent bath. Swish together warm water and any mild liquid detergent. Clean the jewelry with a soft brush while it’s in the suds, then rinse it under warm running water. Pat it dry with a soft, lint-free cloth. Avoid using brushes, which can scratch gold. Never boil gold, and avoid using ammonia, toothpaste, a powder cleanser or scouring pads. Keep gold away from chlorine, lotions, cosmetics and perm solutions, since these products may discolor or dissolve gold alloys. gemstones rarely need cleaning unless they become dirty from hand lotion, hairspray or other products. They can be cleaned using a soft cloth with mild soap and water, but rinse well. If you are using a silver or gold jewelry dip solution, most are safe for gemstones, but read the label to make sure. Do not boil gemstones. Do not wear pearls while applying cosmetics, hair sprays or perfume. It’s best not to wear pearl strands while bathing, because water can weaken the string. Wipe pearl strands with a damp cloth after each use. Do not clean cultured pearls with chemicals, abrasives or jewelry cleaner.

Clear Quartz
A colorless transparent mineral consisting of silicon dioxide in crystal form. See Quartz.

Cleavage
Cleavage is the tendency which a stone has to fracture along its crystal structure.

Clip-on
A piece of jewelry designed to be attached by means of a clip, such as a clip-back earring.

Clip-back Earring
A hinged ring with a pad, called a “comfort back”, at one end to secure the earring to the earlobe without requiring that the ear be pierced.

Cloisonné
Occasionally called “cell enameling”, it is a type of enameling in which compartments made of thin strips of metal soldered onto a metal plate are filled with powdered glass prior to firing. The glass powder melts filling the compartments with solid glass.

Closed Setting
A closed setting is one in which the back of the stone is not exposed (the metal is not cut away behind the stone).

Cloud
A form of inclusion, “clouds” are white milky areas that can found in the diamond.

Cluster
Several stones grouped together in a jewelry setting.

Cluster Brooch
A brooch developed in the 14th century in which a large central gemstone is surrounded by a cluster of smaller gemstones and pearls.

Cluster Earring
A decorative earring made up of a cluster of glass and/or metal beads and stones

Cluster Ring
A ring featuring a central gemstone surrounded by a number of smaller stones.

Cluster setting
A cluster setting is one in which small stones or pearls are set around a larger stone.

Clutch
A device that is slid along a post to secure a piece of jewelry, such as the earring back of a stud for pierced ears.

Cocktail Ring
A large oversized ring set with precious or semiprecious stones popular during the 1940s and 1950s.

Cognac Diamond
A cognac diamond is a cognac-brown diamond (having a color of C7). Most cognac diamonds are mined in Western Australia (in the Argyle Mine). The color is produced by a their low nitrogen content.

Coiffe
A net made of gold or silver threads, decorated with gems or pearls worn on the head.

Coin Silver
A silver alloy that is 80% silver and 20% copper. Many European silver pieces are coin silver and are marked “800”, indicating that 800 parts out of 1000 are silver.

Coin-style edge
see Milgrain edge.

Collar
A necklace worn close around the neck. See also “choker”.

Collarette
A collarette (also known as a bib necklace) is a short necklace with flowing ornaments at the front.

Collet
The ring of metal that surrounds and secures the stone in a bezel setting.

Collet Setting
A collet setting is a very early method of setting gemstones. A collet is a thin, round band of metal that goes all around the stone. One edge of the metal is crimped over the edges of the stone and the other edge is soldered to the metal of the jewelry, holding the stone in place. This closed setting sometimes also had metal claws along the outside to hold the stone even more securely (the claws were not used much after the 1200’s and 1300’s.

Color
One of the 4 C s of diamond grading, the term “color” actually refers to the absence of color in a diamond. A diamond acts like a prism letting light pass through, refracting back to the human eye, into a rainbow of color. The color scale breaks up the subtlety and various grades of a diamond’s color from purest white to yellow and brown. The letters D through Z are used to designate a diamonds color with D being colorless and Z-graded stones having a lot of color.

Colored Diamond
Diamondss can be found in a full spectrum of colors. Colored or “Fancy” diamonds are simply referring to diamonds that are not white.

Colored Gold
An alloy of gold and other metals producing rose, yellow, white, and green shades.

Comfort back
A rubber or plastic pad that goes over the clip end of a clip-on earring to cushion the earlobe.

Comfort Fit
A ring that adds to the comfort of the wearer by being curved on the inside of the shank.

Commemorative Wares
Items used to commemorate an important or historical event, such as a battle, coronation, or wedding.

Compass Ring
A rotating ring that can be used to determine compass direction by using the position of the sun and the time of day.

Composite Suite
A composite suite is a piece of jewelry that can be taken apart into two or more pieces which can also be worn. For example, a necklace may be disassembled into two bracelets.

Concave
Concave simply means “curving inward”, like the inside of an egg shell. The opposite of Convex.

Conch
Conch is a marine animal (a mollusk) with a large, beautiful pearly shell that varies in color, but if often white or pink (pink is the most valued color). Queen conch has a large, pink shell. Conch shell is often used to make jewelry. Conch is made into beads and cameos. Conch has a hardness of 2.85 (it is relatively soft).

Concha
One of the ovals of a segmented silver belt or bridle. Also a reference to the belt itself. Now commonly called a “Concho Belt.” From the Spanish word “concha”, meaning “shell”.

Concho
See Concha.

Condition , Excellent
A piece of jewelry in Excellent Condition will show reasonable evidence of wear, and have a fine patina.

Condition, Fine
A piece of jewelry in Fine Condition may show slight wear, but not enough to have developed a patina.

Condition, Good
A piece of jewelry in Good Condition will show substantial evidence of wear. It will have a noticeable patina which may include numerous very fine pits or lines. It will not have cracks, chips, obviously discolored or poorly replaced stones, evidence of glue or other repairs, or other evidence of hard wear considered to be damage. Damage of any kind is separately detailed in the item description, and generally items with damage appear at very reduced prices in the Bargain section.

Condition, Mint
A piece of jewelry having no signs of wear whatsoever, including no discolored stones. A piece that is in Mint Condition is in virtually the same condition as it was when it left the manufacturer. Considering that vintage jewelry is usually 50 or more years old, and that it likely has been worn, it is obviously quite rare to find a piece that is truly in Mint Condition.

Confetti lucite
Confetti lucite is transparent plastic with glitter or other small pieces of material within it. Whimsical bangles, earrings, pins, necklaces and other jewelry have been made from confetti lucite.

Contra luz opal
Contra luz (also spelled contraluz) opals are transparent opals that show a brilliant play of iridescence only when light shines through the stone. When the light is on the same side as the viewer, the iridescence is not readily seen (this quality makes it difficult to design jewelry using these beautiful gemstones). Contra luz means “against the light.” Unlike other opals, contra luz opals are usually faceted (rather than cabochoned).

Convex
Simply means “curving outward”, like the surface of a ball. The opposite of Concave.

Copper
A common reddish-brown metallic element, copper is the only metal which occurs abundantly in large masses as opposed to small veins or nuggets that must be mined out of other rocks. It is also found in various ores such as chalcopyrite, chalcocite, cuprite, and malachite. When alloyed with tin it forms bronze, and when alloyed with zinc it forms brass. Copper is an excellent conductor of heat and electricity and is widely used for electrical wiring, as well as water piping and corrosion-resistant parts. When in moist conditions, a greenish layer forms on the outside. It has been extracted and used for thousands of years. The name is derived from the Greek “kupros” (the island of Cyprus), called “Cyprian brass”, and known by the Romans as ‘cuprum.’

Coral
Coral is a form of calcium carbonate, (like aragonite or marble), secreted in long chains by coral polyps, who live in colonies under the ocean. Coral can be found all over the world, but the bulk of coral used in jewelry making has always come from the waters off Sardinia and the coast of Sicily, in the Mediterranean. Coral comes in colors from vivid orange, red, and white, to salmon and pale pink (called angelskin coral). In jewelry making, coral is either carved into beads, cameos, and other forms, or is left in its natural branch-like form and just polished. During the mid-Victorian era large cameo brooches of coral finely carved in high-relief floral sprays or faces were popular. It used to be thought that coral protected the wearer, so it was a traditional gift to children. Since it is composed of calcium carbonate, real coral will effervesce if touched with acid. Imitation coral is made from glass, porcelain, or plastic and will not effervesce when touched with acid.

Coral
Coral is an animal that grows in colonies in the ocean. Coral polyps secrete a strong calcium structure that is used in jewelry making. Coral ranges in color from pale pink (called angelskin coral) to orange to red to white to black. The most valued colors are deep red (called noble coral) and pink. In jewelry making, coral is either carved into beads, cameos, or other forms, or is left in its natural branch-like form and just polished. It used to be thought that coral protected the wearer, so it was a traditional gift to children. Coral has a hardness of about 3.5 and a specific gravity of 2.6 to 2.7. Since it is composed of calcium carbonate, coral will effervesce if touched with acid. Imitation coral is made from glass, porcelain, or plastic.

Corallium rubrum
A valuable red coral introduced to the Indians by the Spanish.

Cord belt
A thick belt worn on the waist, usually with a caftan.

Cornelian
Cornelian (also called carnelian and carneole) is a reddish form of chalcedony (a type of quartz). This translucent stone has a waxy luster. The best carnelian is from India. Most commercial carnelian is really stained chalcedony. Carnelian has a hardness of 7 and a specific gravity of 2.61.

Coronet
A small or inferior type of crown worn by a person of high rank but lower than a sovereign.

Coronet setting
See Arcade Setting.

Corundum
The name of a family of stones composed of crystallized aluminum and oxygen that includes rubies and sapphires. The color of these stones depends on the oxides present in their composition. Corundum is one of the hardest minerals second only to diamonds rating a 9 on the Mohs scale. See alumina.

Cowrie Shell
The highly polished and brightly marked shells of tropical marine gastropods of the genus Cypraea, some of which are used as currency in the South Pacific and Africa. Small cowrie shells are commonly used as beads in jewelry.

Crimp Bead
Small soft metal beads that are squeezed shut to secure clasps onto the ends of cords or chains.

Crown
The upper part of a cut diamond or stone above the girdle.

Crown Glass
Crown glass is glass that contains no lead oxide. Some fake rhinestones are made from crown glass.

Crown Height
A measurement of the distance from the girdle to the table on a diamond or other cut stone.

Crystal
A fine, high-quality glass invented in 17th century England. In order to be considered crystal rather than simple glass, the product must contain at least 10% lead oxide. The lead oxide is attributed to providing the glass with extraordinary qualities of brilliance, sound and a suitable texture for cutting or engraving. Some of the finest crystal ever made is from Baccarat in France (est. 1816) and Waterford in Ireland (est. 1729).

Crystal (GLASS)
Crystal is high-quality glass containing at least 10% lead oxide. Lead added to the melt produces very clear glass resembling rock crystal. The process of making lead crystal was discovered by the English glassmaker George Ravenscroft in 1676. Crystal is colored by adding various metallic oxides to the melt.

Crystal (NATURAL)
A crystal is a solid whose atoms form a very regular structure. Some crystals include quartz, diamond, and emerald.

Crystal Habit
Crystal habit is the crystal form that a particular crystal has. The most common crystal habits are:
Prismatic – elongated with parallel sides, like emerald, tourmaline
Tabular – short and flat (table-like), like morganite
Ocatahedral – eight faces, like diamond
Dodecahedral – 12 faces, like garnet
Acicular – needle-shaped, like rutilated quartz
Platy – occurring in very thin plates, like hematite

Crystal Systems
Crystals are divided into seven crystal systems, according to their optical properties (how light bends within the crystal), plane of symmetry, axis of symmetry, center of symmetry, crystallographic axis. Within each of the systems, the cyrstals can mineralize into different crystal habits (form). The seven crystal systems are: cubic systems, tetragonal systems, hexagonal systems, trigonal systems, orthorhombic systems, monoclinic systems, and triclinic systems. For more information on crystal systems, click here.

Crystalline
A substance composed of crystals or resembling crystal in transparency, structure and outline.

Crystallize
To cause a material to form crystals or to assume both the internal structure and external form of a crystal.

Cuban Link Chain
A standard cable chain with oval shaped links that are each decorated with a twisting pattern resembling rope.

Cubic Zirconia (CZ)
A clear, hard, mass-produced gemstone cut to resemble a diamond. The mineral baddeleyite has the same chemical composition, but to become a CZ the mineral must be heated to almost 5000 degrees Fahrenheit and have an oxide stabilizer such as yttrium or calcium added to keep it from reverting back to its original form when cooled. Almost all the rough CZ’s in the market are composed of zirconium oxide and yttrium oxide, both of which are naturally white but combine to form a brilliant clear crystal. Like diamonds, the best cubic zirconia gems are colorless but colored forms are also manufactured. Vivid green CZ is sometimes referred to as C-OX, and CZ in numerous colors is frequently sold under various tradenames, such as the yellow CZ from Ceylon called “jargon”. Cubic zirconia gemstones are cut in the same fashion as diamonds, and like diamonds the size of the gemstone is usually indicated by its weight in carats. The stone can also be measured in millimeter diameter size. Because the cubic zirconia stone is so dense and solid, it outweighs a diamond of the same millimeter size, weighing 1.7 times more than a diamond of the same millimeter diameter. It is also not as hard as a diamond rating only an 8 on the Mohs scale. Natural skin oils, soap, and dirt cause a film that dulls the beauty and luster of the cubic zirconia, just as it dulls real diamonds. The best cleaning agent for cubic zirconia is liquid dishwashing detergent, but other gem and jewelry cleaners can also be used.

Cubic Zirconium
Cubic zirconium (also known as cubic zirconia) is an inexpensive, lab-produced gemstone that resembles a diamond. Cubic zirconia was developed in 1977.

Cuff Bracelet
A wide rigid bangle with a narrow opening on one side to allow the the wrist to pass through.

Cuff link
A decorative fastener worn to close the cuff of a shirt that provides holes on the cuff for the cufflink rather than closing with buttons.

Culet
The tiny flat facet on the tip of the pavilion of a cut gemstone.

Cullinan Diamond
The Cullinan diamond (also called the Star of Africa) is the largest diamond yet found, weighing 3,106 carats (roughly 1.3 pounds) in its rough form. It was mined at the Premier Mine in South Africa in 1905. This enormous gem was named for the chairman of the company that owned the mine. It was given to King Edward VII of England for his birthday in 1907. The diamond was cut (by Joseph J. Asscher of Amsterdam) into many stones, including the Cullinan I (530 carats, pendelique-brilliant shaped, the largest cut diamond in the world), the Cullinan II (317 carats, cushion shaped), Cullinan III (94 carats, pendelique shaped), Cullinan IV (63 carats, square-brilliant shaped), and many other smaller stones.

Cultured Pearl
A means of duplicating the organic process of natural pearl creation invented by Kokichi Mikimoto circa 1893. A tiny irritant like a bead, grain of sand, or a piece of mother of pearl from another mollusk can be inserted into the opening of an oyster or mollusk. This irritant becomes the nucleus of a pearl once that mollusk secretes a lustrous substance (nacre) to cover the foreign body. An oyster or mollusk can take between five to seven years to secrete enough nacre to produce a jewelry quality pearl.

Cupid’s darts
Cupid’s Darts is another name for rutilated quartz.

Curb Link Chain
A chain composed of oval-shaped links that are twisted and often diamond-cut so they lie flat.

Cushion Cut
A stone that is cut to look like a square or rectangle with rounded edges. The cut is usually multi-faceted to give the highest possible light refraction.

Cut
One of the 4 C’s of diamond grading, “cut” refers to the shape and style of a polished gem. How a diamond is cut has a lot to do with the stone’s fire and brilliance. A diamond that is cut either too shallow or too deep will not be as brilliant as a properly cut diamond.

Cut Beads
Cut beads are glass beads that have been faceted. This process makes the bead reflect and refract more light.

Cut glass
Any glass whose surface has been cut into facets, grooves and depressions by a large, rotating wheel. Wheel cutting glass was developed in the 8th century BC, but the technique of faceting wasn’t perfected until the 18th century in England. Although cutting glass is a costly and difficult process, the brilliant effects are extraordinary!

Cut Steel
Cut steel is steel that is cut with a huge number of facets and then riveted to a plate of steel (or other metal). It was widely used in jewelry during the late 18th century, including shoe buckles, buttons, bracelet, necklaces, earrings, hair ornaments, and as a setting for cameos. Early in the 19th century, cut steel quality diminished and was stamped out in strips instead of being individually cut and riveted.

Cut Stones
Common cuts include the brilliant cut, old European cut, emerald cut, radiant cut, rose cut, step cut, pendelique cut. Mixed cuts in which the style of the facets above and below the girdle are different. Other, more unusual cuts, are know as fantasy cuts (like the heart cut).

CZ
See cubic zirconia.
An earring with a drop suspended like a chandelier. Also called a “Drop Earring” or “Dangle Earring”.

Channel Inlay
A design similar to enameling in which stones, rather than melted plastic or glass, are cut to shape and set into the recesses of a piece of jewelry. Commonly seen with jewelry using mother of pearl and turquoise.

Channel Set
A style of setting in which a number of uniformly sized small stones, usually of the round cut, princess cut or baguette shapes, are set side by side in a grooved channel. Unlike most setting methods the stones are not secured individually with prongs and there is no metal visible between the stones.

Chaplet
A garland, wreath, or ornamented band worn around the head. Chaplets are made of metal with repoussé decoration or embellished with gemstones and pearls.

Charm
A pendant or trinket worn on a bracelet, earring or necklace.

Charm Bracelet
A chain link bracelet with charms attached to it. (It’s not a charm bracelet until it has charms attached.)

Charm Ring
A ring with a charm attached to the ring band.

Charoite
Charoite is a fairly recent discovery found in Russia in 1978 in the Murun mountains in Yakutia, near the Charo River. This is the only known location for this rare mineral.
It ranges in color from a light lilac to a deep purple and can be mottled with gray, white and black inclusions. The chatoyant variety in a bright deep purple, is usually considered more valuable than the non-chatoyant variety although both are used in jewelry and compliment a number of other stones.

Chasing
A method of decorating the front, (or outside), of metal objects by making indentations using shaped punches and a chasing hammer. The opposite of chasing is repoussé.

Chatelaine
French for “Lady of the House”, a chatelaine is an ornamental chain or pin worn at a woman’s waist from which dangle keys, trinkets, scissors, needle cases, pencils, purse, etc. Chatelaines may be utilitarian or beautifully decorated and made from precious materials like silver.

Chatham synthetic rubies
Chatham synthetic rubies (laboratory-created rubies) were introduced by Carroll Chatham in 1959.

Chaton
A cone shaped rhinestone or crystal.

Chaton setting
A châton setting (also called coronet or arcade setting) is one in which the stone is held in by many metal claws around a metal ring.

Chatoyancy
Chatoyancy is the lustrous, cat’s eye effect seen in some cabochon stones, like cat’s eye, tiger’s eye (pictured above), and sometimes in other stones, like aquamarine. In chatoyancy, light is reflected in thin bands within the stone. Chatoyant stones are cut in cabochon to maximize the lustrous effect.

Chatoyant
A stone having a changeable luster due to the way it reflects light, such as the cat’s-eye or tiger’s eye gemstones. From the French “chatoyer”, meaning to shimmer like cats’ eyes, from the French “chat” meaning “cat”.

Chenier
Chenier is fine, hollow tubing that is used in the production of some jewelry findings (like clasps and joints), and lately, in the actual production of jewelry. The hollow tubes are lightweight and save in the use of gold. The tubes are hard to bend when they are empty, so a metal rod is inserted before bending, facilitating the bending.

Chevron setting
A chevron is a design found in heraldry resembling a shallow inverted “V”. In jewelry design, a “chevron setting” is reflective of the heraldic chevron in that it is made up of lines in a shallow inverted “V” pattern.

Chinese opal
Chinese opal is a misnomer for pearl opal (a type of organic opal), moonstone, or white chalcedony

Chloride
Any compound containing a chlorine atom.

Chlorine
An abundant element which, when isolated, appears as a poisonous, greenish-yellow gas with a disagreeable odor. It occurs naturally only as a salt, as in sea-water. Chlorine is used widely to purify water, as a disinfectant and bleaching agent, and in the manufacture of many important compounds including chloroform and carbon tetrachloride.

Choker
A close fitting necklace worn tight around the neck like a collar.

Chrome
A hard, brittle, grayish white metal, fusible with difficulty and resistant to corrosion. Its chief commercial importance is for its compounds, as potassium chromate, lead chromate, etc., which are brilliantly colored and are used dyeing and calico printing. The common modern usage is for very shiny metal objects like chrome bumpers, etc.

Chrome diopside
Chrome diopside is an emerald-green colored gemstone. It is a chromium-rich variety of the common mineral diopside (Calcium magnesium silicate). Chrome diopside has a hardness of 5 to 6 and a specific gravity of 3.3 to 3.6.

Chromium
A lustrous, hard brittle, steel-blue metallic element, resistant to corrosion and tarnishing. It is used in the hardening of steel alloys and the production of stainless steels, in corrosion-resistant decorative platings, and as a pigment in glass.

Chronograph
A chronograph is a stopwatch mechanism on a watch; it can be started, stopped and reset independently from the watch.

Chrysoberyl
A rare, hard, yellow-green mineral consisting of alumina and glucina, (beryllium aluminate), in crystal form. It is popular as a gemstone for its chatoyant qualities.

Chrysocolla
Chrysocolla (meaning “golden lime” in Greek) is an opaque blue to blue-green mineral sometimes used in jewelry. It is usually cut as a cabochon. Chrysocolla (hydrated copper silicate) is found embedded in rock crystal in copper mines in the USA, Russia, Chile, and the Congo. Although Chrysocolla has been used in ornaments since the time of the ancient Greeks, it was only described mineralogically in 1968. Its hardness varies from 2 to 4.

Chrysolite
A mineral composed of silica, magnesia, and iron sometimes used as a gem. Chrysolite ranges in color from a light pea green to a deep olive green and an oily shine. It is common in certain volcanic rocks and meteorites. Mystics have claimed that this lustrous green stone drives away evil and has special healing properties. The name chrysolite has been used in the past for yellow varieties of tourmaline and topaz.

Chrysoprase
Chrysoprase is the most valued variety of the mineral chalcedony (microcrystalline quartz) that contains nickel, giving it an apple-green color. Chrysoprase is porous and translucent. It is usually cut as a cabichon, and has been used since ancient times. Chrysoprase has a hardness of 7 and a specific gravity of 2.6. Chrysoprase is mined in Australia, Russia (the Ural Mtns.), Brazil, and the western USA. Chrysoprase is sometimes called “Australian jade,” but it is not related to jade. Hard-to-detect imitation chrysoprase is made by staining agate with chromium salts.

Cigar band
A very wide band-style ring.

Cinnabar
Cinnabar is the mineral Mercury Sulfide. Its color ranges from cinnamon to scarlet to brick red and it can be translucent to transparent. It is often carved. Cinnabar has a hardness of 2 – 2.5 (very soft) and a specific gravity of 8.1 (quite heavy).

Cinnamon stone
A brown or yellowish-brown variety of garnet more properly called “essonite”.

Cire perdu
Cire perdu (French for “lost wax”) is a process of casting metal in which the original model is sculpted in wax. The wax is entombed in clay, and the wax is then melted out, producing a hollow mold. The mold is then filled with molten metal. The clay is broken off and the cast metal remains.

Citrine
Named after the French word for lemon, “citron”. Citrine is often incorrectly called quartz topaz or citrine topaz. A variety of quartz, citrine is found in light yellow, amber-brown, and a brilliant orange that may be confused with fine imperial topaz. Most citrine comes from South America. In ancient times, citrine was revered as a gift of the sun and believed to be a powerful antidote to a viper’s venom. Citrine is the birthstone for November.

Claddagh Ring
First crafted by Master Goldsmith Richard Joyce in 1689, it is named after Claddagh, the fishing village he lived in at the time, which overlooks Galway Bay. The ring belongs to a class of rings called “Fede” or “Faith rings”, which date from Roman times and were popular in the Middle Ages throughout Europe. Whereas “Fede” rings have only two clasped hands, symbolizing faith, trust, or “plighted troth”, Claddagh rings have two hands clasping a heart, symbolizing love, surmounted by a crown, symbolizing loyalty. The ring worn on the right hand with the heart turned outward indicates that your heart is yet unoccupied. Worn on the right hand with the heart turned inward indicates that love is being considered. Worn on the left hand the with the heart turned inward shows everyone that your heart is truly spoken for.

Clarity
One of the 4 C’s of diamond grading. Gemstones with the highest clarity contain few or no inclusions (imperfections) in the stone’s crystalline structure. Clarity is graded with a 10x magnifier. The clarity rating of a diamond ranges from FL (flawless) to I (inclusions visible to the naked eye).

Clasp
A device used to connect two ends of a necklace, bracelet or watch strap. Popular types of clasps include: Barrel, box, Lobster claw, and Spring ring clasps. (See individual listings).

Class Ring
A ring that commemorates graduating from high school. It is usually engraved with the name of the school, the year of graduation, and a gem featuring one of the school’s colors.

Claw
A claw is a metal prong that holds a stone securely in a setting.

Claw Setting
A way of securing a stone in its mount using small prongs that surround it.

Cleaning Jewelry
The safest and easiest way to clean most jewelry is with a detergent bath. Swish together warm water and any mild liquid detergent. Clean the jewelry with a soft brush while it’s in the suds, then rinse it under warm running water. Pat it dry with a soft, lint-free cloth. Avoid using brushes, which can scratch gold. Never boil gold, and avoid using ammonia, toothpaste, a powder cleanser or scouring pads. Keep gold away from chlorine, lotions, cosmetics and perm solutions, since these products may discolor or dissolve gold alloys. gemstones rarely need cleaning unless they become dirty from hand lotion, hairspray or other products. They can be cleaned using a soft cloth with mild soap and water, but rinse well. If you are using a silver or gold jewelry dip solution, most are safe for gemstones, but read the label to make sure. Do not boil gemstones. Do not wear pearls while applying cosmetics, hair sprays or perfume. It’s best not to wear pearl strands while bathing, because water can weaken the string. Wipe pearl strands with a damp cloth after each use. Do not clean cultured pearls with chemicals, abrasives or jewelry cleaner.

Clear Quartz
A colorless transparent mineral consisting of silicon dioxide in crystal form. See Quartz.

Cleavage
Cleavage is the tendency which a stone has to fracture along its crystal structure.

Clip-on
A piece of jewelry designed to be attached by means of a clip, such as a clip-back earring.

Clip-back Earring
A hinged ring with a pad, called a “comfort back”, at one end to secure the earring to the earlobe without requiring that the ear be pierced.

Cloisonné
Occasionally called “cell enameling”, it is a type of enameling in which compartments made of thin strips of metal soldered onto a metal plate are filled with powdered glass prior to firing. The glass powder melts filling the compartments with solid glass.

Closed Setting
A closed setting is one in which the back of the stone is not exposed (the metal is not cut away behind the stone).

Cloud
A form of inclusion, “clouds” are white milky areas that can found in the diamond.

Cluster
Several stones grouped together in a jewelry setting.

Cluster Brooch
A brooch developed in the 14th century in which a large central gemstone is surrounded by a cluster of smaller gemstones and pearls.

Cluster Earring
A decorative earring made up of a cluster of glass and/or metal beads and stones

Cluster Ring
A ring featuring a central gemstone surrounded by a number of smaller stones.

Cluster setting
A cluster setting is one in which small stones or pearls are set around a larger stone.

Clutch
A device that is slid along a post to secure a piece of jewelry, such as the earring back of a stud for pierced ears.

Cocktail Ring
A large oversized ring set with precious or semiprecious stones popular during the 1940s and 1950s.

Cognac Diamond
A cognac diamond is a cognac-brown diamond (having a color of C7). Most cognac diamonds are mined in Western Australia (in the Argyle Mine). The color is produced by a their low nitrogen content.

Coiffe
A net made of gold or silver threads, decorated with gems or pearls worn on the head.

Coin Silver
A silver alloy that is 80% silver and 20% copper. Many European silver pieces are coin silver and are marked “800”, indicating that 800 parts out of 1000 are silver.

Coin-style edge
see Milgrain edge.

Collar
A necklace worn close around the neck. See also “choker”.

Collarette
A collarette (also known as a bib necklace) is a short necklace with flowing ornaments at the front.

Collet
The ring of metal that surrounds and secures the stone in a bezel setting.

Collet Setting
A collet setting is a very early method of setting gemstones. A collet is a thin, round band of metal that goes all around the stone. One edge of the metal is crimped over the edges of the stone and the other edge is soldered to the metal of the jewelry, holding the stone in place. This closed setting sometimes also had metal claws along the outside to hold the stone even more securely (the claws were not used much after the 1200’s and 1300’s.

Color
One of the 4 C s of diamond grading, the term “color” actually refers to the absence of color in a diamond. A diamond acts like a prism letting light pass through, refracting back to the human eye, into a rainbow of color. The color scale breaks up the subtlety and various grades of a diamond’s color from purest white to yellow and brown. The letters D through Z are used to designate a diamonds color with D being colorless and Z-graded stones having a lot of color.

Colored Diamond
Diamondss can be found in a full spectrum of colors. Colored or “Fancy” diamonds are simply referring to diamonds that are not white.

Colored Gold
An alloy of gold and other metals producing rose, yellow, white, and green shades.

Comfort back
A rubber or plastic pad that goes over the clip end of a clip-on earring to cushion the earlobe.

Comfort Fit
A ring that adds to the comfort of the wearer by being curved on the inside of the shank.

Commemorative Wares
Items used to commemorate an important or historical event, such as a battle, coronation, or wedding.

Compass Ring
A rotating ring that can be used to determine compass direction by using the position of the sun and the time of day.

Composite Suite
A composite suite is a piece of jewelry that can be taken apart into two or more pieces which can also be worn. For example, a necklace may be disassembled into two bracelets.

Concave
Concave simply means “curving inward”, like the inside of an egg shell. The opposite of Convex.

Conch
Conch is a marine animal (a mollusk) with a large, beautiful pearly shell that varies in color, but if often white or pink (pink is the most valued color). Queen conch has a large, pink shell. Conch shell is often used to make jewelry. Conch is made into beads and cameos. Conch has a hardness of 2.85 (it is relatively soft).

Concha
One of the ovals of a segmented silver belt or bridle. Also a reference to the belt itself. Now commonly called a “Concho Belt.” From the Spanish word “concha”, meaning “shell”.

Concho
See Concha.

Condition , Excellent
A piece of jewelry in Excellent Condition will show reasonable evidence of wear, and have a fine patina.

Condition, Fine
A piece of jewelry in Fine Condition may show slight wear, but not enough to have developed a patina.

Condition, Good
A piece of jewelry in Good Condition will show substantial evidence of wear. It will have a noticeable patina which may include numerous very fine pits or lines. It will not have cracks, chips, obviously discolored or poorly replaced stones, evidence of glue or other repairs, or other evidence of hard wear considered to be damage. Damage of any kind is separately detailed in the item description, and generally items with damage appear at very reduced prices in the Bargain section.

Condition, Mint
A piece of jewelry having no signs of wear whatsoever, including no discolored stones. A piece that is in Mint Condition is in virtually the same condition as it was when it left the manufacturer. Considering that vintage jewelry is usually 50 or more years old, and that it likely has been worn, it is obviously quite rare to find a piece that is truly in Mint Condition.

Confetti lucite
Confetti lucite is transparent plastic with glitter or other small pieces of material within it. Whimsical bangles, earrings, pins, necklaces and other jewelry have been made from confetti lucite.

Continenta
Continental was a Canadian costume jewelry company that produced good-quality pieces, usually studded with colorful rhinestones.

Contra luz opal
Contra luz (also spelled contraluz) opals are transparent opals that show a brilliant play of iridescence only when light shines through the stone. When the light is on the same side as the viewer, the iridescence is not readily seen (this quality makes it difficult to design jewelry using these beautiful gemstones). Contra luz means “against the light.” Unlike other opals, contra luz opals are usually faceted (rather than cabochoned).

Convex
Simply means “curving outward”, like the surface of a ball. The opposite of Concave.

Copper
A common reddish-brown metallic element, copper is the only metal which occurs abundantly in large masses as opposed to small veins or nuggets that must be mined out of other rocks. It is also found in various ores such as chalcopyrite, chalcocite, cuprite, and malachite. When alloyed with tin it forms bronze, and when alloyed with zinc it forms brass. Copper is an excellent conductor of heat and electricity and is widely used for electrical wiring, as well as water piping and corrosion-resistant parts. When in moist conditions, a greenish layer forms on the outside. It has been extracted and used for thousands of years. The name is derived from the Greek “kupros” (the island of Cyprus), called “Cyprian brass”, and known by the Romans as ‘cuprum.’

Coral
Coral is a form of calcium carbonate, (like aragonite or marble), secreted in long chains by coral polyps, who live in colonies under the ocean. Coral can be found all over the world, but the bulk of coral used in jewelry making has always come from the waters off Sardinia and the coast of Sicily, in the Mediterranean. Coral comes in colors from vivid orange, red, and white, to salmon and pale pink (called angelskin coral). In jewelry making, coral is either carved into beads, cameos, and other forms, or is left in its natural branch-like form and just polished. During the mid-Victorian era large cameo brooches of coral finely carved in high-relief floral sprays or faces were popular. It used to be thought that coral protected the wearer, so it was a traditional gift to children. Since it is composed of calcium carbonate, real coral will effervesce if touched with acid. Imitation coral is made from glass, porcelain, or plastic and will not effervesce when touched with acid.

Coral
Coral is an animal that grows in colonies in the ocean. Coral polyps secrete a strong calcium structure that is used in jewelry making. Coral ranges in color from pale pink (called angelskin coral) to orange to red to white to black. The most valued colors are deep red (called noble coral) and pink. In jewelry making, coral is either carved into beads, cameos, or other forms, or is left in its natural branch-like form and just polished. It used to be thought that coral protected the wearer, so it was a traditional gift to children. Coral has a hardness of about 3.5 and a specific gravity of 2.6 to 2.7. Since it is composed of calcium carbonate, coral will effervesce if touched with acid. Imitation coral is made from glass, porcelain, or plastic.

Corallium rubrum
A valuable red coral introduced to the Indians by the Spanish.

Cord belt
A thick belt worn on the waist, usually with a caftan.

Cornelian
Cornelian (also called carnelian and carneole) is a reddish form of chalcedony (a type of quartz). This translucent stone has a waxy luster. The best carnelian is from India. Most commercial carnelian is really stained chalcedony. Carnelian has a hardness of 7 and a specific gravity.

Corundum
The name of a family of stones composed of crystallized aluminum and oxygen that includes rubies and sapphires. The color of these stones depends on the oxides present in their composition. Corundum is one of the hardest minerals second only to diamonds rating a 9 on the Mohs scale. See alumina.

Cowrie Shell
The highly polished and brightly marked shells of tropical marine gastropods of the genus Cypraea, some of which are used as currency in the South Pacific and Africa. Small cowrie shells are commonly used as beads in jewelry.

Crimp Bead
Small soft metal beads that are squeezed shut to secure clasps onto the ends of cords or chains.

Crown
The upper part of a cut diamond or stone above the girdle.

Crown Glass
Crown glass is glass that contains no lead oxide. Some fake rhinestones are made from crown glass.

Crown Height
A measurement of the distance from the girdle to the table on a diamond or other cut stone.

Crystal
A fine, high-quality glass invented in 17th century England. In order to be considered crystal rather than simple glass, the product must contain at least 10% lead oxide. The lead oxide is attributed to providing the glass with extraordinary qualities of brilliance, sound and a suitable texture for cutting or engraving. Some of the finest crystal ever made is from Baccarat in France (est. 1816) and Waterford in Ireland (est. 1729).

Crystal (GLASS)
Crystal is high-quality glass containing at least 10% lead oxide. Lead added to the melt produces very clear glass resembling rock crystal. The process of making lead crystal was discovered by the English glassmaker George Ravenscroft in 1676. Crystal is colored by adding various metallic oxides to the melt.

Crystal (NATURAL)
A crystal is a solid whose atoms form a very regular structure. Some crystals include quartz, diamond, and emerald.

Crystal Habit
Crystal habit is the crystal form that a particular crystal has. The most common crystal habits are:
Prismatic – elongated with parallel sides, like emerald, tourmaline
Tabular – short and flat (table-like), like morganite
Ocatahedral – eight faces, like diamond
Dodecahedral – 12 faces, like garnet
Acicular – needle-shaped, like rutilated quartz
Platy – occurring in very thin plates, like hematite

Crystal Systems
Crystals are divided into seven crystal systems, according to their optical properties (how light bends within the crystal), plane of symmetry, axis of symmetry, center of symmetry, crystallographic axis. Within each of the systems, the cyrstals can mineralize into different crystal habits (form). The seven crystal systems are: cubic systems, tetragonal systems, hexagonal systems, trigonal systems, orthorhombic systems, monoclinic systems, and triclinic systems. For more information on crystal systems, click here.

Crystalline
A substance composed of crystals or resembling crystal in transparency, structure and outline.

Crystallize
To cause a material to form crystals or to assume both the internal structure and external form of a crystal.

Cuban Link Chain
A standard cable chain with oval shaped links that are each decorated with a twisting pattern resembling rope.

Cubic Zirconia (CZ)
A clear, hard, mass-produced gemstone cut to resemble a diamond. The mineral baddeleyite has the same chemical composition, but to become a CZ the mineral must be heated to almost 5000 degrees Fahrenheit and have an oxide stabilizer such as yttrium or calcium added to keep it from reverting back to its original form when cooled. Almost all the rough CZ’s in the market are composed of zirconium oxide and yttrium oxide, both of which are naturally white but combine to form a brilliant clear crystal. Like diamonds, the best cubic zirconia gems are colorless but colored forms are also manufactured. Vivid green CZ is sometimes referred to as C-OX, and CZ in numerous colors is frequently sold under various tradenames, such as the yellow CZ from Ceylon called “jargon”. Cubic zirconia gemstones are cut in the same fashion as diamonds, and like diamonds the size of the gemstone is usually indicated by its weight in carats. The stone can also be measured in millimeter diameter size. Because the cubic zirconia stone is so dense and solid, it outweighs a diamond of the same millimeter size, weighing 1.7 times more than a diamond of the same millimeter diameter. It is also not as hard as a diamond rating only an 8 on the Mohs scale. Natural skin oils, soap, and dirt cause a film that dulls the beauty and luster of the cubic zirconia, just as it dulls real diamonds. The best cleaning agent for cubic zirconia is liquid dishwashing detergent, but other gem and jewelry cleaners can also be used.

Cubic Zirconium
Cubic zirconium (also known as cubic zirconia) is an inexpensive, lab-produced gemstone that resembles a diamond. Cubic zirconia was developed in 1977.

Cuff Bracelet
A wide rigid bangle with a narrow opening on one side to allow the the wrist to pass through.

Cuff link
A decorative fastener worn to close the cuff of a shirt that provides holes on the cuff for the cufflink rather than closing with buttons.

Culet
The tiny flat facet on the tip of the pavilion of a cut gemstone.

Cullinan Diamond
The Cullinan diamond (also called the Star of Africa) is the largest diamond yet found, weighing 3,106 carats (roughly 1.3 pounds) in its rough form. It was mined at the Premier Mine in South Africa in 1905. This enormous gem was named for the chairman of the company that owned the mine. It was given to King Edward VII of England for his birthday in 1907. The diamond was cut (by Joseph J. Asscher of Amsterdam) into many stones, including the Cullinan I (530 carats, pendelique-brilliant shaped, the largest cut diamond in the world), the Cullinan II (317 carats, cushion shaped), Cullinan III (94 carats, pendelique shaped), Cullinan IV (63 carats, square-brilliant shaped), and many other smaller stones.

Cultured Pearl
A means of duplicating the organic process of natural pearl creation invented by Kokichi Mikimoto circa 1893. A tiny irritant like a bead, grain of sand, or a piece of mother of pearl from another mollusk can be inserted into the opening of an oyster or mollusk. This irritant becomes the nucleus of a pearl once that mollusk secretes a lustrous substance (nacre) to cover the foreign body. An oyster or mollusk can take between five to seven years to secrete enough nacre to produce a jewelry quality pearl.

Cupid’s darts
Cupid’s Darts is another name for rutilated quartz.

Curb Link Chain
A chain composed of oval-shaped links that are twisted and often diamond-cut so they lie flat.

Cushion Cut
A stone that is cut to look like a square or rectangle with rounded edges. The cut is usually multi-faceted to give the highest possible light refraction.

Cut
One of the 4 C’s of diamond grading, “cut” refers to the shape and style of a polished gem. How a diamond is cut has a lot to do with the stone’s fire and brilliance. A diamond that is cut either too shallow or too deep will not be as brilliant as a properly cut diamond.

Cut Beads
Cut beads are glass beads that have been faceted. This process makes the bead reflect and refract more light.

Cut glass
Any glass whose surface has been cut into facets, grooves and depressions by a large, rotating wheel. Wheel cutting glass was developed in the 8th century BC, but the technique of faceting wasn’t perfected until the 18th century in England. Although cutting glass is a costly and difficult process, the brilliant effects are extraordinary!

Cut Steel
Cut steel is steel that is cut with a huge number of facets and then riveted to a plate of steel (or other metal). It was widely used in jewelry during the late 18th century, including shoe buckles, buttons, bracelet, necklaces, earrings, hair ornaments, and as a setting for cameos. Early in the 19th century, cut steel quality diminished and was stamped out in strips instead of being individually cut and riveted.

Cut Stones
Common cuts include the brilliant cut, old European cut, emerald cut, radiant cut, rose cut, step cut, pendelique cut. Mixed cuts in which the style of the facets above and below the girdle are different. Other, more unusual cuts, are know as fantasy cuts (like the heart cut).

CZ
See cubic zirconia.

Dalsheim
Dalsheim and “White Jet” are marks on costume jewelry made by Dalsheim Accessories, Inc. of New York, New York, USA. The company was founded by Maurice Dalsheim. These relatively rare marks were first used in 1939.

Damascening
Damascening is the inlaying of a soft metal (like silver or copper) into a hard metal (like steel). The name comes from the city of Damascus, where this process was first used.

Danburite
Danburite (Calcium borosilicate – CaB2Si2O8) is a clear to white silicate mineral whose orthorhombic crystals are transparent to translucent (danburite can also be yellow, greenish, or brown); it resemblestopaz. It was named for the city of Danbury in Fairfield County, Connecticut, USA (where the original specimens were found in 1839). Danburite is also found in Russell, New York (USA), Charcas and San Luis Potosi (Mexico), Kyushu Island (Japan), Madagascar, Siberia, Mogok (Myanmar), Bolivia, and Uri (Switzerland). Danburite has a hardness of 7 – 7.3 and a specific gravity of 2.97 – 3.02. Its streak is white.

Darya-i-Nur
Darya-i-Nur (meaning “Sea of Light”) is one of the largest-known diamonds. It is a flawless, transparent, pink diamond from India, weighing about 175 to 195 carats. It was taken to Prrsia (now Iran) after Persia’s attack on Delhi, India, in l739. The Darya-i-Nur is in the crown jewels of Iran, and was worn by the Shah of Iran.

Dead Pawn
Dead pawn is an item that was pawned but was never collected by the original owner.

“Dead” Stone
A “dead” stone is a foil-backed rhinestone that has lost its original shininess, usually after water has damaged the foil. For example, a “dead” clear rhinestone will appear dull and off-white, greenish or yellowish.

Dead Soft
Dead soft is a term that refers to very soft-tempered metal. Dead soft wire is the most easily bent wire. For example, copper electrical wire is dead soft.

Demantoid Garnets
Demantoid garnets are valuable green, very lustrous garnets with a cubic crystalline structure. They are a rare variety of andradite. Demantoid garnets have characteristic inclusions that look like horsetails. Demantoid garnets have a hardness of 6-7 and a specific gravity of 3.8 – 3.9. Demantoids were very popular in the 1800’s, but are rarely used today.

Demilune
A demilune (meaning “half moon”) stone is shaped like a half (or smaller) moon.

Demi-Parure
A demiparure is a matching set of jewelry, usually containing a necklace, earrings, and a pin. See parure. The demi-parure above is a set by Trifari.

Dendritic
Dendritic means tree-like, having a branching pattern (like moss agate).

Denim Lapis
Denim lapis is a relatively pale, inexpensive variety of lapis lazuli that is from Chile. It is the color of denim cloth due to calcite inclusions (which whiten the stone and lower its value).

Dentelle
Dentelles (meaning “lace” in French) are rhinestones cut with 32 or 64 facets.

Diadem
A diadem is a tiara, a circular or semi-circular piece of jewelry worn on the head.

Diamanté
Diamanté is another word for rhinestone.

Diamond
Diamonds are precious, lustrous gemstones made of highly-compressed carbon. Diamonds are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 – 2.419. Colors of diamonds range from colorless, yellow, orange, brown, to almost black. Rarer colors are red, blue, green, and purple; these colors (called fancies) are quite valuable. Canary diamonds have a deep yellow color. A diamond’s value is based on the “4 C’s”: color, cut, clarity, and carat weight. A diamond’s color (saturation) is rated on an alphabetical scale ranging from D (white) to Y (yellow). “Z” diamonds are fancy, or deep-colored diamond. A diamond’s cut is designed to maximize the stone’s natural “fire”; brilliant cuts are preferred. A diamond’s clarity depends on the number and size of its flaws and inclusions (of other minerals, like quartz). Clarity is rated from FI (flawless), IF (flawless at 10x magnification), a series of V ratings (very small flaws at 10x magnification), a series of S ratings (small flaws at 10x magnification), to I1, I2, and I3 (having inclusions visible to the naked eye). A diamond’s carat weight is simple how much it weighs (a carat is about 0.2 grams or about 0.007 ounces). The largest-known gem-quality diamonds include the Cullinan (aka the Star of Africa, 530.20 carats), the Excelsior, the Great Mogul (an ancient Indian diamond which is said to have originally weighed 787.5 carats, but its location is not not known and nothing about it has been authenticaed), the Darya-i-Nur, the Koh-i-Nur, and the Hope diamond (named for a purchaser, Henry Thomas Hope).

Diapering
Diapering is a crisscross pattern of diamond-shaped lines on a raised-dot enamel pattern.

Dichroic Glass
A glass which contains ultra-thin layers of aluminum, chromium, silicon, zirconium or the metal alloy titanium. The colors are almost holographic in appearance.
Addition of the various elements is what produces the bold and dramatic colors. Colloidal gold may also be added. The appearance will be different depending on whether the light is reflected or transmitted.

Dichroism
Dichroism is the property of having more than one color, especially when viewed from different angles. Many minerals (like rubies and axinite) are naturally dichroic. This effect can be artificially caused by a thin layer of a metallic oxides that is deposited on the surface of a material. Dichroic coated glass transmits some wavelengths of light and reflecting others, giving it an opal-like appearance.

Die Stamping
Die stamping (also known as machine-stamping) is a process in which sheet metal is cut and shaped between two dies, forming a pattern in relief. Two steel dies are used, the male die has the design in cameo (protruding); the female die has the design hollowed out. The male die is put on top of the metal, the female die is put on the underside of the metal. The press is forcefully brought down onto the dies and metal, forcing the metal into the shape of the mold. Many medallions and mass-produced jewelry findings are made this way.

Diffusion
Diffusion is the process of color enhancing a stone by heating the stone in the presence of iron oxide, chrome oxide or similar compounds. The process colors the stone by infusing the outside surface of the stone with color. Only applied to cut stones as any further cutting would remove the color enhancement. This process is often used on sapphires and topaz to heighten or alter the colors.

Diffusion Treated
Diffusion treated stones are color-enhanced (not naturally colored) stones. The diffusion process only colors the outer surface of the stone, so chipping or repolishing will result in a loss of color. Diffusion-treated stones are already-cut stones that are heated in the presence of other compounds (like iron oxide, chromium oxide, titanium dioxide, etc.) that will infuse the extreme outer surface stone with color. Under a microscope, you you can see the loss of color within each tiny scratch. Diffusion treatment can also change the stone’s refractive index. Also, if the stone is faceted, the color will appear stonger where the facets meet.

Dinosaur Bone
Petrified Dinosaur Bone or”dino bone” is the result of fossilized bone from dinosaurs in which the cellular structure has been replaced with quartz, leaving the bone structure intact.

Dog Collar
A dog collar (also known as “collier de chien”) is a type of short, multiple-strand choker-style necklace that fits tightly against the neck. Dog collars are also known as ” plaque de cou” (meaning “neck badge”) when they are fastened by a clasp in the front. Dog collars are 14″-15″ in length.

Dog Tag Jewelry
Dogtag jewelry is based on the dogtags issued to soldiers. This type of necklace has become popular recently. Dogtag necklaces consist of a flat, dogtag-shaped pendant strung on a silver ball chain.

Dolomite
Dolomite (calcium magnesium carbonate, CaMgCO3) is a common type of sedimentary rock. Dolomite occurs in crystals and in masses. This mineral was named for the French mineralogist Déodat de Dolomieu (1750-1801), who first described it in 1791.

Domed
A convex shape like the outside surface of a ball or sphere. This shape is often used in earrings, pendants and components of jewelry designs.

Doublet
A doublet (also dublette) is a gem made from two layers in order to save expenses; the lower part of the composite stone is glass or a non-precious stone, the top is the more valuable stone. Many different types of doublets have been manufactured (including opal doublets). One common doublet contains a layer of real garnet and a layer of glass. A thin, red garnet top is glued to a colored glass bottom. A green glass bottom with a red garnet top layer produces an emerald-like stone. A diamond is enlarged by cementing it to a crystal base.

Doubly Refractive Stone
In doubly-refractive stones, lthe light entering the stone is split into two light rays, and the rays travel in different paths. These stones have more than one refractive index. Calcite, peridot, zircon, tourmaline, and titanite are doubly-refractive stones. Bi-refringence is another name for double refraction.

Drawn Bead
Drawn beads are cut from a long, straw-like tube of glass (the tube is made by drawing a hot mass of glass fresh from the furnace). The sharp-edged cut beads are often tumbled and reheated to give them rounded edges. Some examples of drawn beads include seed beads, bugle beads, furnace glass beads, and pony beads.

Drop Cut
A drop cut (or briolette) is a pear-shaped cut gemstone with triangular facets on top. This type of stone makes a nice pendant.

Drusy
Drusy (sometimes referred to as: druse, druzy) is a layer of tiny quartz crystals that form on a host stone. The cavity inside a geode is sometimes filled with drusy quartz crystals. Although the quartz crystals may be the source of the color (amethyst, citrine), usually it is the host stone’s color (chrysocolla, uvarovite garnet) that shows through the quartz and gives the stone its color. (pronounced: dru-zee)

Druze
Druze is a layer of crystals that form within a mineral crust, like the inner cavity of a geode. Amethyst crystals are often found in a druze. The inner cavity of agate geodes are often lined with a druze of sparkling quartz crystals.

Ductile
A ductile substance is easily pulled or stretched into a thin wire. gold is the most ductile metal.

Dull
The term used to describe gems which exhibit an earthy or dull luster, meaning their surface does not reflect light very well. Plastic can be described as having a dull luster as is clay. Hematite that does not have a highly polished surface will display a dull luster.

Dumortierite
Dumortierite (Aluminum Boro-silicate Hydroxide) is a blue to violet silicate mineral that is used as an ornamental stone (and sometimes as a semi-precious stone in jewelry). Dumortierite quartz is a massive variety of opaque quartz that is intergrown with dumortierite crystals. Dumortierite has a hardness of 7 – 8.5 and a specific gravity of 3.3 – 3.4.

DWT.
A measure of Troy weight, dwt. is the abbreviation for “pennyweight”, a measure used to weigh gold, silver, and jewels. In Troy weight, the pound = 12 ounces, the ounce = 20 pennyweights, and the pennyweight = 24 grains. While this method of weighing is believed to have originated in Cairo during the crusades, the name comes from Troyes, France where it was first used .

Ebonite
Ebonite (also called vulcanite) is a hard, moldable, polished dark colored (ranging from brown to black) early rubber. Ebonite was produced by adding sulfur to vulcanized rubber. It was used for combs, ornaments, and buttons. Ebonite is sometimes confused with gutta percha.

Ebony
Ebony is a hard, dark, dense wood sometimes used in jewelry.

Eilat Stone
Eilat stone is only found in King Solomon’s copper mines on the Red Sea, near Eilat, Israel. This opaque green mineral is composed of azurite, malachite, turquoise, and chrysocolla. The hardness of this copper-based stone varies. There are many variations on its spelling, including Eliat, Elat, and Ellat.

Electroplating
Electroplating (also called Galvanotechnics after its inventor, Luigi Galvani) is a process in which one metal is coated with another metal using electricity. In jewelry, inexpensive metals are frequently electroplated with more expensive metals, like gold (gold plating), copper (electrocoppering), rhodium (rhodanizing), chromium (chromium plating), or silver (silver plating). The thickness of the metal coat varies. Electrogilded coating is the thinnest (less than 0.000007 inches thick); gold-cased metals have a coating thicker that 0.000007 inches.

Electrum
Electrum is an amber-colored alloy of gold and silver that was used in ancient times. Electrum is also an alloy used in medieval times consisting of copper (50%), nickel (30%) and zinc (20%).

Elie Ruby
An Elie ruby is actually a pyrope garnet (and not a ruby at all).

Email
Email (French for enamel) is a method in which enamel is applied to metal. It can be applied in many different ways, including cloisonné, champlevé, and plique à jour.

Emboss
Embossing is a method of surface decoration in which a design is raised slightly above the surface. Sheets of metal, leather, and plastic can be embossed.

Emerald
Emeralds are a very hard, green precious stone (beryl, Be3Al2Si6O18, colored by chromium and some vanadium impurities). Flaws and cloudiness (called jardin) are very common in emeralds, so many emeralds are oiled, irradiatied,and dyed to improve their look. Synthetic emeralds (developed by Carroll Chatham in the 1930’s) have fewer imperfections and are very hard to distinguish from natural emeralds. Emeralds belong the beryl group of stones which also includes aquamarines, morganite, and chrysoberyl). Emeralds have a hardness of 7-8 and a specific gravity of 2.6 – 2.8. Emerald (and all forms of beryl) have large, perfect, six-sided crystals. Emeralds were long thought to have healing powers, especially for eyesight. During the renaissance, emeralds were used as a test for friendship among the aristocracy; an emerald given to a friend would remain perfect as long as the friendsip endured.

Emerald cut
Emerald cut stones have a girdle that is rectangular with truncated corners. Emerald cuts are frequently used on emeralds and diamonds.

Enamel
Enamel is a glassy substance (powdered glass with colorants) fused onto metal using heat (see cloisonné, champlevé, guilloche, and plique à jour).

ENGRAVE
Engraving is a method of surface decoration in which a design is etched into the surface with a sharp tool.

Enhanced
Enhanced stones are stones that have been treated to improve their color, clarity, finish, strength, or other characteristics. Some common enhancements are heat-treatment, irradiation, coating the surface, filling cracks, oiling, surface diffusion (coating the surface then applying heat), bleaching, dyeing, etc.

Etched Finish
An etched finish on a metal’s surface reduces the metal’s reflectivity. It is done by using harsh chemicals to eat into the surface or by cutting into the surface using a sharp tool.

Eternity Ring
An eternity ring is a narrow ring with gemstones set all around it.

Etruscan Jewelry
Ancient Etruscan jewelry has intricate and beautiful designs; most is made of gold. The Etruscans employed a lot of delicate granulation (n which tiny beads of gold are soldered to the surface to form a pattern) and openwork filagree (in which filagree patterns are not applied over sheet metal). The Etruscans lived in Northern Italy for hundreds of years beginning in the late 8th century B.C.

Etui
An etui (also called a necessaire) is a tiny, decorative, cylindrical-shaped case that was often carried on a chatelaine. The etui was used to carry small “necessary” items like pencils, scissors, manicure set, or spectacles. The etui was first used in the 1720’s.

European Cut
The European cut (also known as the old European cut) is an old, round diamond cut that is similar to but less bright than the newer brilliant cut. The European cut has a very small table and heavy crown.

EverGreen Topaz
EverGreen (R) is a trademarked type of diffusion-treated topaz. This deep green stone is produced by heating a cut, colorless topaz with coloring chemicals (mineral oxides), resulting in a thin layer of green coating the outside of the stone.

Eyepin
An eyepin is a thin wire with a loop at one end; it is used for linking beads together.

Excelsior Diamond
The Excelsior is the second or third largest diamond (depending on whether or not the Braganza diamond was actually a diamond). This irregular-shaped blue-white diamond was roughly 995 carats. It was found in l893 by a worker at the De Beers mine at Jagersfontein, Orange Free State, South Africa. The Excelsior diamond was cut in 1904 by I.J. Asscher and Company of Amsterdam into 21 stones, including a 69.80-carat marquise, an 18-carat marquise stone (which was displayed at the l939 World’s Fair by the De Beers company), and many other stones.

Facet
A facet is one of the flat surfaces of a cut stone or glass.

Faceting
Faceting is the cutting and polishing of the surface of a stone.

Fancy Diamonds
Fancy diamonds are rare diamonds that are red, blue, green, or purple; these diamonds are quite valuable. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 – 2.419.

Fancy Cut
Fancy cut stones are cut in unusual ways. Some fancy cuts include the heart, fan, rivoli, trapezium, cathedral window, half-moon (lunette), kite, and triangle.

Fantasy Cut
The fantasy cut is a new way of faceting stones that uses freeform angles – virtually anything goes.

Fashion Jewelry
Fashion jewelry is another name for costume jewelry. The Trifari leaf pin above is gold-plated and has glass stones.

Faux
Faux means false. A faux gem is an imitation.

Feather
A feather is an internal flaw (also called an inclusion) in a gemstone that can start at the surface of the stone and extend deep inside. Feathers can either ruin a stone (by making it fragile and/or changing the color), or add to its beauty.

Fede Ring
A fede ring is one that depicts two hands clasped together.

Feldspar
Feldspars are a family of minerals that include moonstone (adularia), amazonite, sunstone, and labradorite.

Fenichel
Fenichel is a very rare costume jewelry mark. Fenichel pieces are well made, often using high-quality rhinestones and/or enamel on rhodium-plated metal.

Ferrer’s Emerald
Ferrer’s emerald is a glass stone made to imitate an emerald.

Fetish
A fetish is a charm, amulet, pendant or other decoration associated with magical properties; it often represents an animal or person.

Fibula
A fibula is a brooch (pin) that looks a bit like a safety pin. Fibulas have been used since ancient times to secure clothing.

Figural
Figural jewelry is disigned to look like real objects. Common subjects are the human body, animals (especially butterflies, dogs, cat, birds, and shells), flowers, leaves, and everyday objects (like baskets and fans).

Filigree
Filigree is gold or silver wire that have been twisted into patterns and soldered into place. Openwork filigree is not soldered onto a sheet of metal and is difficult to make. Imitation filigree is made of stamped metal.

Findings
Findings are the parts that jewelers use in making jewelry. For example, clasps, hooks, pin backs, jump rings, and earring backs are findings.

Fineness
Fineness is the proportion of silver or gold in a metal alloy. Fineness is usually expressed in parts per thousand. For example, the fineness of sterling silver is 925.

Finger Ring Size
To size a finger for a ring, a finger-ring gauge is used. The rings are marked with their size and the person determines which one fits well. Another, less accurate method is a cardboard card with cut-out holes marked with the ring sizes. To determine the ring size of a finger using the circumference of the finger, or to determine the size of a ring given its diameter, the formulas are:

Fire
A stone’s fire is the streaks of brilliant color within it. Good quality opals, like the one above, have a lot of fire.

Fire Opal
Fire opals are a type of opal that is fiery orange to red in color (but have no opalescence). These opals are rarely transparent – they are usually milky. Opal is a mineral composed of silica (and some water) and is a species of quartz. Many opals have a high water content – they can dry out and crack if they are not cared for well (opals should be stored in damp cotton wool). Opals have a hardness of 5.5 to 6.5 and a specific gravity of 1.98-2.50. Fire opals are found in Western Australia, Mexico, Brazil, Guatemala, and Honduras.

Firestone
Firestone is an imitation iridescent rainbow quartz. It is made by heating rock crystal until it crazes; iIt is then put into dye as it cools.

Flaw
A flaw is a an imperfection in a gemstone. Flaws include: cracks, inclusions of other minerals or liquid-filled cavities. A flawless stone is called “clean.” Flaws can greatly reduce the value of a stone, but in some cases, like moss agate or rutilated quartz, the “flaws” increase the value of the stone.

Floater Necklace
An floater (or invisible) necklace looks as though the beads are simply floating on the skin; the beads or pearls are strung far apart from one another on an almost invisible string (like clear fishing line).

Florentine Finish
A Florentine finish on a metal’s surface reduces the metal’s reflectivity. It is accomplished by engraving parallel lines into the surface using a sharp tool, and then making more lines or curves at right angles (cross-hatching).

Flowering Obsidian
Flowering Obsidian (also called snowflake obsidian) is a volcanic glass that is usually dark (black or brownish) with white “snowflakes”. This glassy, lustrous mineral is found in lava flows, and obsidian stones can be massive. Obsidian is formed when viscous lava (from volcanos) cools rapidly. Most obsidian is 70 percent silica. Obsidian has a hardness of 5 and a specific gravity of 2.35.

Fluorescence
Fluorescence is property in which light (or other radiation) is emitted from an object. Many stones (including some diamonds) flouresce when exposed to ultraviolet light.

Fluorite
Fluorite is a mineral that comes in many colors, including purple, clorless, red, pink, yellow, green, blue, black, and multi-colored stones. Crystals are transparent to translucent. Fluorite is relatively soft – it has a hardness of 4 and a specific gravity of 3.0 – 3.3. The chemical formula for fluorite is CaF2. Fluorite is frequently fluorescent (various varieties fluoresce red, blue, green or yellow light). Fluorite is found all around the world. Some varieties of fluorite include: Blue John (purple with bands of white or yellow), Chlorophane (thermoluminescent – emitting bright green light when heated), Yttrofluorite (yttrium replaces some of the calcium – formula = [Ca,Y]F2), Yttrocerite (cerium and yttrium replaces some of the calcium in its structure – formula = [Ca,Ce,Y]F2, Antozonite (contains uncombined fluorine ions – when fractured or cleaved, it gives off an odd odor).

Fob
A fob is a short chain or ribbon that attaches to a pocketwatch; it frequently had a decorative medallion or other ornament attached to one end. Fobs were worn hanging from a pocket. Fob is also the word for the small pocket in trousers that held a pocket watch. The word fob is also commonly used for the fob charm itself.

Foilback
A foilback (or foiled stone) is a stone that has a metallic foil backing; this thin metallic backing is frequently composed of mercury and tin. Silver-colored, gold-colored, or other-colored foil is applied to the back of a stone to make the stone more reflective. Before scintillating cuts (like the brilliant cut) were invented, even precious stones were foiled to enhance their sparkle. Moisture can damage foil and make the stone “dead,” losing its brilliance. Stones are rarely foiled any more.

Fold Over Clasp
A fold over clasp is a jewelry fastener that is composed of a device that opens and closes with a hinge, and latches shut. It is used to attach the two ends of a necklace or bracelet.

Fool’s Gold
Fool’s gold is pyrite, a shiny, metallic mineral that looks like gold, but is actually a a form of iron. Marcasite stones come from pyrite.

Fossil Ivory
Fossil ivory is the tusk of the extinct Woolly Mammoth (an elephant-like animal that lived during the last Ice Ages).

FOSSILS
Fossils are the remains of ancient animals and plants, the traces or impressions of living things from past geologic ages, or the traces of their activities. Fossils can be used to make beautiful jewelry. Fossils came in many different mineral and organic forms, including plain-looking rocks, marble-like casts of ancient animals, opals, and amber (fossilized tree resin).

Fracture
A fracture is a crack in a gemstone (also called a feather).

Freeform
A stone cut in an unusual or non-calibrated shape

French Enamel
French enamel refers to fine enamel work (like the work of Fabergé) the was first developed in France. In this technique, many thin layers of translucent colored enamel (glass paste with colorants) are applied to a metal surface. After firing the piece at temperatures of up to about 820°C, the work is polished. A final layer of clear enamel often covers the piece. Fine miniature paintings in enamel on a white-enamel ground have been produced in France since this technique was developed in 1620-1630 by the French goldsmith Jean Toutin of Chateaudun and other French goldsmiths.

French Ivory
“French Ivory” is synthetic (imitation) ivory. It is molded from plastics (like celluloid) and is also called Ivoride, Ivorine, and “Genuine French Ivory.”

French Jet
French jet is black glass (pyrolusite glass) designed to imitate real jet. It was frequently carved.

Freshwater Pearl
A freshwater pearl is a pearl that was harvested from a freshwater mussel (a mollusk). These pearls are frequently shaped like crisped rice cereal, and are less valuable than oyster pearls. Biwa pearls are very good quality freshwater pearls.

Frost Agate
Frost agate is agate with white markings (that look like frost).

FUCHSITE
Fuchsite is a deep emerald green variety of the mineral muscovite that is rich is the chromium. It has a glassy luster. Fuchsite is relatively soft; it has a hardness of 2-2.5 and a specific gravity of 2.77-2.88. The chemical formula for fuchsite is K(Al,Cr)2(AlSi3O10)(OH)2.

Full Cut
A full cut stone is a gemstone with 58 facets.

Furnace Glass
Furnace glass (also called furnace worked glass) is made by working (shaping) hot glass by hand (the glass was heated in a glass furnace). Long tubes of glass are drawn from molten glass, then beads are cut from the tube (and later tumbled and reheated to smooth the edges of the beads). Furnace glass beads are made in a wide variety of colors, shapes, and designs.

Gablonz
Gablonz (Jablonec nad Nisou) is a city in the Czech Republic, in Bohemia, that is a center of jewelry making. Before World War 2, Gablonz was a center of high-quality glass-blowing, bead-making, and other costume-jewelry related products.

Gadroon
A series of small vertical, diagonal or twisted grooves applied as a border decoration on silverware.

Gagate
Gagate (popularly known as jet) is fossilized coal. It is a hard, lustrous black stone that was used in mourning jewelry during the Victorian era (especially after Queen Victoria’s husband died and she went into a long-lasting mourning, affecting fashion). Jet is frequently cabochon cut. Gagate has been mined near Whitby (on the Yorkshire coast of England) since prehistoric times. It is also found in Spain. France, Germany, and Russia, but these other sources are said to be inferior to the harder, more elastic Whitby jet. Jet/gagate has a hardness of 2.5-4 (quite soft) and a specific gravity of 1.30-1.35 (it is relatively lightweight). Jet leaves a brown streak. When burnt with a red-hot needle, jet smells like coal Black glass and plastics are often used to imitate jet (glass is much heavier and harder than jet) – jet is warm to the touch.

Gahnospinel
Gahnospinel is a rare blue spinel stone that is high in zinc and magnesium. It can only be distinguished from most spinel by its high specific gravity and high refractive index. Gahnospinel has a hardness of 8, a specific gravity of 3.97. Its chemical formula is (Mg, Zn)Al2O4.

Gallery
A type of mounting with a pierced, openwork design resembling the gallery, (rear platform), of an early sailing ship.

Garland Style
A jewelry style popular in the early 20th century made possible by the introduction of the widespread use of platinum and characterized by lightness and delicacy that employed motifs such as garlands, ribbon bows, swags, and tassels.

Garnet
A family of stones having many varieties differing in color and in their constituents, but all are silicates with the same isometric crystallization and conforming to the same general chemical formula. Garnet is a very commonly found in gneiss and mica slate. The name is derived from its resemblance in color and shape to the seeds of the pomegranate. The most common color of garnets range from light red to violet or plum-red, but can also be white, green, yellow, brown, and black varieties. It seems as though every shade and color of garnet is given its own name. Known varieties of garnet include Andradite, Tsavorite, Grossularite, Essonite, Pyrope, Almandine, Spessartite, Melanite, Allochroite, Ouvarovite, Demantoid, and Rhodalite. (See individual listings). Garnets have a hardness that varies between 6-8 on the Mohs scale. It was believed that the wearer of garnets was kept in good health and protected while traveling. Garnets are worn to signify truth and faith. Red garnet is the birthstone for January.

Gaspeite
Gaspeite is a pale green to apple-green semi-precious gemstone that often has brown inclusions of its host rock. Gaspeite is translucent to opaque. This beautiful stone has only recently been used in jewelry, and is often set in silver. Gaspeite has a hardness of 4.5 – 5, and a specific gravity of 3.7. Gaspeite is Nickel Magnesium Iron Carbonate; its chemical formula is (Ni, Mg, Fe)CO3. This stone is found in Gaspe Peninsula, Quebec, Canada (where it was originally found and from which it derives its name) and Kambalda and Widgie Mooltha, Western Australia, Australia

Gem
A precious or semiprecious stone that may be used as a jewel when cut and polished. Include diamond, beryl, emerald, chalcedony, agate, onyx, tourmaline, chrysolite, sapphire, ruby, spinel, topaz, turquoise, zircon, cubic zirconia, jacinth, hyacinth, carbuncle, amethyst, alexandrite, cat’s eye, bloodstone, hematite, jasper, moonstone, sunstone, and many others. Several organic materials like coral and pearls are also considered gemstones.

Gemstone
Today, the common definition of a gemstone is any precious or semi-precious stone, rock or mineral.
The explicit definition of a gemstone is a precious stone: diamond, ruby, sapphire, emerald and precious opal.
Semiprecious stones are any other rocks, minerals, or petrified material that is not classified as precious and which is used in jewelry or collected. Some semi-precious stones include: agate, topaz, carnelian, and jasper, lapis lazuli, jade and turquoise.

Genuine
Unless the word “genuine” is included in the description of a piece of jewelry, it could simply be using the term to describe the color of the piece rather than its actual content. For example, “gold” meaning gold toned, rather than actual gold. (See below) Or “amethyst” meaning amethyst colored, rather than containing an actual amethyst stone.

Genuine Pearl
A smooth, round growth used as a gem, a “genuine” pearl is one that formed naturally within the shell of a mollusk due to an irritant rather than having the irritant placed into the mollusk by hand or being made out of plastic.

Geode
A geode is a rock whose crystal-filled interior can be hollow or filled. The crystals that form within the mineral crust of the geode is called druze. From the outside, geodes look like rounded, but otherwise ordinary rocks.

German Silver
German silver (also know as nickel silver) is an alloy consisting of mostly copper (roughly 60 percent), and approximately 20 percent nickel, about 20 percent zinc, and sometimes about 5 percent tin (then the alloy is called alpaca). There is no silver at all in German silver. This alloy was invented around 1860 in Germany as a silver substitute.

GIA
GIA stands for the Gemological Institute of America.

Gilding
An object decorated with a thin layer of gold, gold leaf or gold foil.

Gilt
Gold plated.

Gimmel Ring
A gimmel ring is a double ring that was designed during the Renaissance. It consists of two or more interlocking rings. A gimmel ring symbolizes the union of two people.

Gipsy Setting
The gipsy setting is a recessed setting in which the stone is sunk into the metal. There are often engraved designs around the stone (especially star patterns). This type of setting was developed in the late 1800’s and was often used for rings. The gipsy setting is also known as the “star setting.”

Girandôle
A style of earring or brooch in which a large stone or decorative element suspends three smaller pear-shaped pendants of similar design.

Girasol
Girasol (which means sunflower in Spanish) is a yellow or orange type of precious opal. Girasol is also known as hyacinth opal. In girasol, the play of colors seems to come from within the stone, like a floating light, and seems to follow the light source.

Girdle
The outermost edge of a cut gem when viewed from the side and top. It is the edge formed by where the top section (crown) and the bottom section (pavilion) of the cut stone meet.

Givre Beads
Givré beads are beads made of transparent glass fused around a translucent core. Givré means frost in French.

Glass
Glass is often used in jewelry, as beads (faceted or spherical), rhinestones and as poured glass.

Glass Paste
Glass paste (also known as pate de verre) is glass that is ground into a paste, put into a mold, and then melted. The final piece is an opaque, dense glass with a frosted surface.

Glove Ring
A glove ring is a clip-like device that is used to attach one’s gloves to a purse (or other object). The glove ring has a clip on one end (for the gloves) and a chain with a clasp on the other end (to attach the device to a purse handle).

Glucinum
(Also called “Beryllium”) A rare silver-white metallic element resembling magnesium. It is only found in nature combined with other elements, usually silica or alumina, in the minerals phenacite, chrysoberyl, beryl, euclase, and danalite.

Glyptography
Glyptography is the art of engraving gemstones, making intaglio and cameos. Stones are engraved using grindstones with powdered emory or diamond as an abrasive

Gneiss
A form of granite, but having the component materials, especially the mica, arranged in planes so that it breaks rather easily into coarse slabs or flags.

Gold
A yellow precious metal which is valued for its beauty and purity since it does not oxidize or tarnish like most other metals. It has been used for coins and jewelry for over 6000 years and from this has become regarded as a symbol of wealth. Gold is very ductile and is the most malleable of all metals. It can be cast into huge statues or beaten into wafer thin sheets of gold leaf. This malleability makes it too soft to be used in jewelry without being alloyed with other metals. (See Karat).

Gold Dore
Gold doré (pronounced gold doh-ray) is a bar of semi-purified gold (e.g. bullion). After being mined, the first stage in the purification process of the gold ore produces a cast bar (gold dore) that is approximately 90% gold. The other 10% is mostly metals like silver and copper.

Gold electroplating
Process by which sheets of gold of at least 10 karats and no less than seven-millionths of an inch thick are electro-chemically bonded to another metal.

Gold Filled
(Also “Goldfilled”, or “gold-filled”, abbreviated g.f.) A piece of jewelry with a layer of gold mechanically applied to the surface of a base metal, (like brass or copper), can be called Gold Filled if the amount of gold equals one-twentieth of the total weight of the piece. Victorian pieces are likely to be unmarked, but later pieces are marked with the fineness of the gold layer, and the part by weight of the gold. For example a piece marked “1/10 12K G.F.” is composed of at least 1/10 12K gold based on the weight of the finished piece. An older unmarked gold piece may often be identified by wear through to base metal, especially when viewing corners or edges under magnification. Look for a change to a darker, brassy colored material at these spots.

Gold Plated
Gold-plated metal has a very thin layer of gold on the surface, usually applied by the process of electroplating. Pieces that are gold plated are often marked G.E.P., gold electroplate, gold plated, or electro-plaqué d’or.

Gold Stone
Goldstone (also known as aventurine) is a shimmering quartz stone that ranges in color from yellow to red to light green to light brown. The shimmer is caused by tiny metallic particles (mica) within the stone (not gold).

Gold Tone
Jewelry finished with a gold color with almost no appreciable measurement of weight in actual gold.

Gold Washed
Products that have an extremely thin layer of gold, (less than .175 microns thick), applied by either dipping or burnishing the metal, but not plated.. This will wear away more quickly than pieces that are gold plated, gold-filled, or gold electroplated.

Golden finish
Jewelry finished so that it has the look of gold, but no actual gold content.

Golden Valadium
Stainless steel that has been electro-charged to resemble real yellow gold.

Goldstone
See Aventurine.

Good Condition
A piece of jewelry in Good Condition will show substantial evidence of wear. It will have a noticeable patina which may include numerous very fine pits or lines. It will not have cracks, chips, obviously discolored or poorly replaced stones, evidence of glue or other repairs, or other evidence of hard wear considered to be damage. Damage of any kind is separately detailed in the item description, and generally items with damage appear at very reduced prices in the Bargain section.

Goshenite
Goshenite is the pure, colorless form of beryl (Be3AlSiO6, related to emerald and aquamarine). This hard, transparent gemstone is named for the town of Goshen, Massachusetts, where it was first found. Goshenite has been found in North and South America (especially Colombia), Northern Europe, East Africa, South Africa, and the Himalayan mountains in Asia. Goshenite has a hardness of 7.5 – 8.0 and a specific gravity of 2.6 – 2.8. It is not enhanced. Goshenite is sometimes coated with a green foil to resemble an emerald.

Gothic revival
Jewelry that evokes the feeling of medieval Europe in its use of styles, symbols, and motifs. It began in the 18th century as part of the romantic movement.

Gram Weight
The weight, in grams, of a specific metal used in a piece of jewelry.

Graduated
A graduated necklace of beads or pearls has beads that go from a small size in the back of the neck and gradually increase in size to a maximum in the front of the necklace.

Grain
A grain is a unit of weight used for diamonds and natural pearls. Four grains are equal to one carat

Granite
A common igneous rock composed of quartz, orthoclase, and hornblende, often accompanied by pyroxene or mica. It is called granite because of the granular surface. Granite is frequently used for buildings and monuments.

Granulation
A technique often used in Etruscan Revival jewelry, granulation is the application of minute granules or grains of metal to the surface of a piece of jewelry to form a decorative pattern.

Grape Garnet
Grape garnets are a rare, intense violet to purple-red garnet. Grape garnets are made up of almandite and spessartite. They have a hardness of 7-7.5 and a specific gravity of 3.8 – 3.9. Grape garnets are found in the Orissa district of northwestern India.

Greasy
Used to describe a gemstone’s luster. Some gems which exhibit a greasy luster are: nephrite jade, jadeite, soapstone, and talc.

Greek key
A design motif attributed to the ancient Greeks symbolizing the bonds of love, friendship and devotion. Greek key designs are repeating patterns of interlocking geometric shapes.

Green Diamond
Green diamonds are rare, fancy diamonds and are quite valuable. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 – 2.419.

Green Garnet
Green garnets are Demantoid garnets, a valuable green, and very lustrous type of garnet. They are a rare variety of andradite. Demantoid garnets have characteristic inclusions that look like horsetails. Demantoid garnets has a hardness of 6-7 and a specific gravity of 3.8 – 3.9. Demantoids were very popular in the 1800’s, but are rarely used today.

Green gold
An alloy made of gold mixed with copper, silver, zinc and often cadmium. The copper is what gives it the greenish tinge. It is commonly used with enameling to strengthen the color of the gold when set beside the bright enamels.

Green Rouge
Green rouge is chromium dioxide, which is used to polish precious metals, giving them a luster.

Greenstone
Greenstone is another name for nephrite, a semi-precious stone and a variety of jade. Nephrite is slightly softer that jadeite and is often veined; it is used in carvings, for making beautiful bowls and vases.

Grelot
Grelots are small beads that have an elongated, pendant shape.

Grey Gold
Grey gold is gold that has been alloyed with 15-20% iron.

Griqualandite
Griqualandite is tiger’s eye from Griqualand, South Africa. It is a yellowish-brown to reddish-brown gemstone that has a silky luster. This gemstone has bands of yellow and brown; when viewed from the opposite direction, the colors are reversed. Tiger’s eye is usually highly polished and set as a cabochon (or cut as a bead) to display the stone’s chatoyancy (light reflected in thin bands within the stone). Tiger’s eye is a type of chatoyant quartz with fibrous inclusions (especially crocidolite). This stone is sometimes heat-treated. Tiger’s eye has a hardness of 7.0.

Grooved
The channel routed in a line.

Grossular
Resembling a gooseberry, as with a grossular garnet, also called Grossularite.

Grossular Garnet
Grossular garnet is a type of garnet, calcium-aluminum silicate. Hessionite is a transparent brown, yellow, orange, or honey-colored variety of grossular garnet often used in jewelry. The yellow variety is called cinnamon stone, hyacinth or jacinth. Transvaal “jade” is a type of green to gray grossular garnet from South Africa. Pink grossular garnets varieties include landerite, rosolite, andXalostocite. Tsavorite is an emerald-green grossular garnet. Grossular garnet has a hardness of 6-7.5 and a specific gravity of 3.6.

Grossularite
A translucent garnet of a pale green color like that of the gooseberry, occurring alone or as a constituent of the common garnet. It may also be pink, brown, or black.

Guilloché
A style of enameling in which a continuous decoration is engraved by an engine-turned lathe and then covered with translucent enamel so that the engraving can be seen through the enamel.

Gunmetal
Gunmetal is a metal alloy that is composed of 90 percent copper and 10 percent tin.

Gypsum
A soft, white mineral composed of hydrous sulfate of lime. It is used as plaster of Paris.

Gypsy Ring
A gypsy ring (also spelled gipsy) is a ring with a recessed stone or stones. Also known as “star setting.”

Gypsy setting
A setting in which the surface of the mount is virtually flush with the top of the gemstone.

Hair Jewelry
Hair jewelry is jewelry containing or composed of locks of hair. This type of jewelry was popular in the mid-1800’s as a remembrance of deceased loved ones.

Hallmark
A hallmark is an official mark (or a series of marks) made in metal that indicates the fineness of the metal and the manufacturer’s mark. For example, a hallmark of 925 indicates 925 parts of gold per 1000 weight. Other hallmarks indicate the maker of the piece and sometimes the year of manufacture. In many countries (like Britain) it is illegal to hallmark metal incorrectly; some countries are notoriously lax in their enforcement of hallmark honesty.

Hammered Metals
Hammered metals have been formed, shaped, or decorated by a metalworker’s hammer. The surface of hammered metal is covered with crater-like depressions made by a hammer. Many hammered metals are used in jewelry including gold, silver, brass, aluminum, etc. The pin above is hammered silve

Hardness
Hardness is measured using the Mohs Scale of Hardness. A substance’s hardness value indicates the materials resistance to scratching and grades minerals on a comparative scale from 1 (very soft) to 10 (very hard).. In the Mohs scale, a mineral of a given hardness rating will scratch other minerals of the same rating, as well as any minerals of a lower rating. For example, sapphires and rubies have a Mohs rating of 9 and will scratch each other, as well as any mineral with a rating lower than 9. However, they will not scratch diamonds, which are rated 10. The Mohs scale of mineral hardness was devised by the German mineralogist Frederich Mohs (1773-1839) in 1812.
Substance Hardness
Talc 1
Amber, Fingernail, Ivory, Shell, Jet 2.5
Gold 2-3
Bronze, Coral, Pearl 3
Iron 4
Glass 5
Opal 5.5-6.5
Amethyst, Chalcedony, Quartz, Steel (pocket knife) 7
Spinel, Topaz 8
Ruby, Sapphire 9
Diamond 10

Hawk’s Eye
Hawk’s eye is a green, grey or blue variety of quartz that has parallel, fibrous inclusions of crocidolite that give it a greenish cat’s eye effect (chatoyancy). This mineral has a silky luster. It looks a lot like Tiger’s Eye, and often occurs with it in the same rock, but the internal structure is different.

Heat Treatment
Heat treatment is the heating of stones to a high temperature in order to enhance the color or clarity. For example, blue-green aquamarine becomes blue with heat treatment and brown zircon becomes blue or clear.

Heishi
Heishi (pronounced he-she) is jewelry made from disk-shaped beads of shell (or turquoise, lapis lazuli, and other stones). Each bead begins as a tiny flat piece of shell (or stone). A tiny stringing hole is drilled though the fragment. Many of these jagged pieces are strung together tightly on a wire and are then sanded into evenness using a fine-grained sandstone and then sandpaper. The result is a very smooth strand of disk-shaped beads. This is an ancient form of bead-making developed by the Pueblos of North America.

Helenite
Helenite is a manmade (not natural) green glass that is made from “rock dust” (not volcanic ash) taken from the vicinity of the Mt. St. Helens volcano in Washington state. The dust is fired to 2700 degrees F, forming glass, which is later faceted and used as a gemstone. This glass is sometimes called emerald obsidianite or Mount St. Helens obsidian (but it is not obsidian, which is a natural glass). Helenite is sold as a souvenir of the eruption of Mt. St. Helens on May 18, 1980. The composition of rock from Mt. St. Helens is: Rock from Mt. St. Helens is composed of: silicone 60.50%, aluminum 16.60%, iron 6.02%, calcium 5.36%, sodium 4.18%, manganese 2.59%, potassium 1.20%, titanium .90%, phosphorus .35%, magnesium .12%, strontium .06%, Beryllium .04%, copper .03%, lead .03%, zirconium .02%, chromium .02%, and zinc .02%; the remaining 0.16 percent is sulfur, chlorine, and water.

Heliotrope
Heliotrope (commonly known as bloodstone) is an inexpensive type of chalcedony that is green with red highlights (caused by iron oxide). Heliotrope is porous and relatively soft.

Hemalyke
Hemalyke is a synthetic hematite that is made by grinding up hematite, adding a binder (glue) and then press-molding it. The stone is sometimes faceted. Hemalyke looks very much like natural hematite – it is very difficult to them apart.

Hematite
Hematite (sometimes spelled haematite, and also known as kidney ore) is a lustrous, opaque, blue-black to silvery gray mineral often used in jewelry. Hematite is iron oxide (Fe2O3). Hematite has a hardness of 6.5 and a specific gravity of 4.95 to 5.16. When powdered, hematite is red; when rubbed on a hard stone, it leaves a red streak. Hematite was often used as seal stones, cut as intaglio. It is also used as beads and is faceted, carved or cut as a cabochon for use as a gemstone. The ancient Egyptians carved hematite into scarabs. Hematite is found in England, Mexico, Australia, Brazil, and the Lake Superior region of North America.

Hessonite
Hessonite (also called “cinnamon stone”) is a cinnamon-brown to orange gemstone variety of grossular garnet. Hessonite’s formula is Ca3Al2Si3O12; manganese that gives it its characteristic brown color. This transparent stone has a hardness of 6.5 – 7 and a specific gravity of 3.6. Hessonite is found in Sri Lanka, Brazil, Madagascar, Canada, and California, USA. This stone is not enhanced.

Hook And Eye Clasp
A hook and eye clasp is a simple and ancient jewelry fastener that is composed of a hook and a circular piece that the hook can latch onto. It is used to attach the two ends of a necklace or bracelet.

Howlite
Howlite is a soft, white to gray mineral that takes dye very easily, and can be dyed to imitate turquoise very well (and is sometimes unscrupulously sold as turquoise). Howlite was named for its discoverer, Henry How, a Nova Scotia geologist.

Hyacinth
Hyacinth is a semi-precious stone that is also known as jacinth. it is a lustrous orange-yellow, orange-red, or yellow-brown type of zircon. Hyacinth has a hardness of 7.5 and a specific gravity of 4.65. Sometimes, topaz and grossular garnet of this color are also referred to as hyacinth (this can be very confusing). Hyacinth is mined in Sri Lanka. Even more confusing is the origin of the name, which comes from the Greek hyakinthos, which refers to blue gemstone.

Hyacinth Opal
Hyacinth opal (also known as girasol) is a yellow or orange type of precious opal. In this opal, the play of colors seems to come from within the stone, like a floating light, and seems to follow the light source.

I.D. bracelet
I.D. is short for “Identification”, so an I.D. bracelet is simply a curved plate engraved with the name or initials of the person wearing it.

IGI
Stands for the “International Gemological Institute”. It is the largest independent gem certification and appraisal service in the United States.

Igneous
A substance produced under conditions involving intense heat, such as that which is found in volcanoes. Igneous rock is rock formed by solidification from molten magma.

Imperial Jade
Imperial jade is another name for emerald jade. It is a fine emerald-green color.

Imperial Topaz
Imperial topaz is golden orange-yellow topaz; it is the most valuable type of topaz.

Imperial Mexican Jade
Imperial Mexican jade is not jade at all; it is calcite that has been dyed green.

Import
The act of bringing or carrying in goods from an outside source for trade or sale, especially in regards to goods from a foreign country.

Inca Emerald
Inca emerald is an emerald that is mined in Equador.

Inclusion
A naturally occurring flaw, (feather, fracture, fissure, carbon spot, or cloud), within a diamond or other stone. The test for clarity looks for these flaws.

Indian Agate
Indian agate is another term for moss agate.

Indicolite
Blue Tourmaline.

Ingot
Metal cast into a bar or other shape.

Inlaid
Past tense of inlay.

Inlay
A decorative technique in which part of the surface of a piece of jewelry, furniture, or ceramic is cut away and stone, mother of pearl, or some other substance is imbedded into the hollowed-out area so that it is level with the surface of the piece.

Intaglio
Italian for “carving”, an Intaglio is a carved gem wherein the design is engraved or carved into the object so that it sits below the surface plane of the material, as opposed to a cameo in which the design is raised from it’s background, in relief. This technique was often used for seals, which made a raised impression in wax used to seal a letter or authenticate a document. It was commonly attached to watch fobs, since the watch fob is a good manner of carrying a seal. Once seals fell out of common use, the intaglio tended to face out to the viewer rather than down as on a seal. Some of the most commonly found Victorian intaglios were carved in carnelian, an orange-brown variety of chalcedony.

Intergrown
Intergrown crystals occur when two mineral crystals grow together and become one.

Inverall Sapphire
Inverall sapphires are a type of sapphire from Inverall, New South Wales

Investment Compound
An investment compound is a refractory material (it can withstand extreme heat) which is slightly porous (so that gases from molten metal can escape) and can be formed into a mold (which will be used in metal casting). An example of an investment compound is plaster of paris mixed with silica, boric acid, and graphite.

Invisible Necklace
An invisible (or floater) necklace looks as though the beads are simply floating on the skin; the beads or pearls are strung far apart from one another on an almost invisible string (like clear fishing line).

Invisible Set
A method of setting square gemstones side by side in two or more rows within a metal border or frame so that they are flush against one another with no metal separating them.

Iolite
(also called dichroite or water sapphire). A silicate of alumina, iron, and magnesia which is usually violet-blue, but can be deep blue, light blue-gray, and yellow-white. Makes a beautiful transparent gemstone which is remarkable for its dichroism.

Iridescent
A display of lustrous rainbow-like colors. The colors seen in an oil slick or mother of pearl are good examples of iridescence. Synonymous with “Pearlescent”.

Iridium
A metal of the platinum family often alloyed with platinum to improve workability. Pieces marked “80% Plat. 20% Irid” would indicate that the alloy is 80 % platinum and 20% iridium.

Irish Diamond
Irish diamond is not a diamond at all; it is rock crystal from Ireland.

Iron
The most common metallic element which usually appears dark brown, from oxidation or impurity, but when pure is silvery-white. Iron is found abundantly in nature, usually in combined forms such as hematite, limonite, magnetite, and taconite. It is frequently alloyed in a wide range of important structural materials like cast iron, steel, and wrought iron. It is easily oxidized (rusted) by moisture, and is attacked by many corrosive agents.

Iron Pyrite
See Pyrite.

Irradiated Diamons
Irradiated diamonds are diamonds that have been exposed to radiation. This changes the diamond’s color (as the radiation changes the crystalline structure of the diamond). The change in the diamond is permanent. Older radiation treatments involving exposing the stone to radium; newer treatments bombard the stone with atomic particles in a cyclotron (which accelerates protons, neutrons, or alpha-partices to high speeds). The irradiated stones take on a greenish or an aquamarine hue. Irradiations of diamonds was first done in 1904 by Sir William Crookes, who exposed diamonds to radium, giving them a permanent greenish color; his diamonds are still slightly radioactive (at the level of radium-painted watch). Newer irradiation techniques bombard the crystal with atomic particles in a cyclotron, and then the stone is heated to about 800 degrees Centigrade, producing a stone with very little radioactivity and a permanent color change.

Irradiation
The process of bombarding a gemstone with X-rays, gamma rays or streams of subatomic particles in order to change the stone’s color.

Italian Lipis
Italian lapis is not lapis; it is actually blue-dyed jasper from Italy.

Ivoride
See French Ivory.

Ivory
A hard, smooth yellowish-white substance made from the tusks of elephants and walruses.

Jacinth
A semi-precious stone that is also known as hyacinth. it is a lustrous orange-yellow, orange-red, or yellow-brown type of zircon. Hyacinth has a hardness of 7.5 and a specific gravity of 4.65. Sometimes, topaz and grossular garnet of this color are also referred to as hyacinth (this can be very confusing). Hyacinth is mined in Sri Lanka. Even more confusing is the origin of the name, which comes from the Greek hyakinthos, which refers to blue gemstone.

Jade
A semi-precious stone that ranges in color from green to white to lilac to brown to almost black. Translucent jade is more highly valued than opaque jade. Jade is often cabochon set; stones with imperfections are often carved (the imperfections are simply carved away). Two different minerals are known as jade: jadeite and nephrite. Jadeite is the harder of the two; it is usually used in jewelry production. Nephrite is slightly softer and is often veined; it is used in carvings, for making beautiful bowls and vases. The Chinese have prized jade for thousands of years and regarded it as having medicinal properties when worn or ingested as a powder. Natural jadeite is called Type A or Grade A jade (waxing or wax dipping is allowed). Jadeite that had been bleached and then treated with polymers (plastic) or waxes is called Type B or Grade B jade (it is less durable than natural jade). Jadeite that had been dyed is called Type C or Grade C jade (the color is less durable than that of natural jade). Jadeite that has been both dyed and impregnated with polymers is called Type B+C or Grade B+C.

Jade Glass
Jade glass is translucent green glass that is designed to imitate jade.

Jadeite
Jadeite is the harder of the two varieties of jade. Jadeite is harder (compared to nephrite) and is usually used in jewelry production.

Japanned
A Japanned finish in jewelry is when metal is finished with a lustrous, black lacquer. The Maltese cross brooch above is by Weiss; it has red paste stones and a Japanned finish.

Jasper
A common, opaque, semi-precious stone that is found in many colors, including white, brown, yellow, red, and green. Jasper is found all over the world; it is often striped, speckled, and multi-colored. Jasper has been used for intaglio carvings. Jasper is a type of quartz belonging to the chalcedony family. It is often sealed with petroleum products. Jasper is sometimes dyed to resemble lapis lazuli and misleadingly called “Swiss lapis.” Jasper has a hardness of 6.5 to 7.0.

Jasperine
Jasperine refers to any type of banded jasper.

Jasperized Wood
Jasperized wood (also called xyloid jasper) is petrified wood. It is wood that has fossilized – all the original chemicals have been replaced with minerals, making a stone-like replica of the original wood.

Jasper Ware
Jasper ware (also spelled jasperware) is a type of porcelain (high-fired white kaolin clay) made by the Wedgwood company. It is made into molded cameos that are made into pins, pendants, and necklaces.

Jelly Belly
A jelly belly is a piece of jewelry (usually a pin) that has a clear lucite or glass center. The Trifari jelly belly fish pin above has a faceted glass belly.

Jet
Jet (also known as gagate) is fossilized coal. It is a hard, lightweight lustrous black stone that was used in mourning jewelry during the Victorian era (especially after Queen Victoria’s husband died in 1861 and she went into long period of mourning, greatly affecting jewelry fashion). Jet is frequently cabochon cut. Most jet is from Whitby, England; jet has been mined near Whitby (on the Yorkshire coast of England) since prehistoric times. It is also found in Spain, France, Germany, and Russia, but these other sources are said to be inferior to the harder, more elastic Whitby jet. Jet has a hardness of 2.5-4 (quite soft) and a specific gravity of 1.30-1.35 (it is relatively lightweight). Jet leaves a brown streak. When burnt with a red-hot needle, jet smells like coal. Black glass and plastics are often used to imitate jet (glass is much heavier and harder than jet) – jet is warm to the touch.

Jewelry
Jewelry (spelled jewellery in Britain) is articles of personal adornment, like rings, necklaces, bracelets, cuff links, and pins. Jewelry is made from metals (especially gold and silver), stones, glass, plastic, and other materials.

Job’s Tears
Job’s tears (Coix lacryma-jobi) is a wild tropical grass plant that has very hard seeds. The white seeds are used as beads in jewelry. The seeds are dried, dyed or painted, polished, drilled and then strung into necklaces and bracelets.

Juliana-Style
Juliana-style jewelry is unsigned costume jewelry that resembles Juliana jewelry (see the previous entry)s, but the piece’s origin in undetermined.

Jump Ring
A jump ring is a circular metal ring with an opening. It is used to attach two other rings or links, and is then soldered or pressed shut.

K
See Karat.

Karat
A variation of the word “carat”, (used to describe the weight of a gemstone), “karat”, with a “k” is used to describe the purity of gold. Gold is often alloyed with silver, copper, and/or other metals to improve its strength and durability. Products made from gold are marked to show how much actual gold is contained in the product. Items marked 24K are 100% pure gold. Items marked 18K or 750 have 750 parts gold out of 1000, or 75% pure gold. Items marked 14K or 585 have 585 parts out of 1000, or 58.5% pure gold. Much of the jewelry manufactured before the 20th century do not have these marks and must be tested to determine purity.

Karatclad
Karatclad is a trademark for a very thick gold electroplating process; this type of plating is about 14 times thicker than standard electroplating.

Keeper Ring
A keeper ring is a ring which is used alongside another, more valuable ring to keep it securely on the finger.

Ketoh
See Bow Guard.

Keum Boo
A jewelry-making technique from Korea where 24k gold foil is fused to sterling silver.

Keystone
A keystone is a stone cut the shape of a keystone in an arch. Keystones are usually step cut. The costume jewelry manufacturer Schreiner uses keystones in many of its pieces.

King Cut
The king cut is a modification of the brilliant cut which is used for large diamonds. This cut has 86 facets.

Knife Wire
An extremely thin wire holding a gemstone making it appear to float.

Knot
A knot is a flaw (a mineral inclusion) in a gemstone (usually a diamond) that is ar the surface of a gem after polishing. The know is a small raised bump on the finished gemstone.

Koh-oh-i-nur
The Koh-i-Nur (meaning “Mountain of Light”) is one of the largest-known diamonds. It was found in India and belonged to the first Indian Rajahs of Malwa (in the 1300s). The gem made its way to Persia in the 1500s (taken as a spoil of war by the Mogul Sultan Babur). At some point it was returned to Indiabut was taken by the East India Company and presented to Queen Victoria of England in 1850. Tge gem was later cut and set into a brooch and later into the State Crown of the United Kingdom. The Koh-i-Nur is part of the crown jewels of England and is kept in the Tower of London, London, England.

Korite
See Ammolite.

Koroit Opal
Opals from the Koroit mines in Australia. These are the hardest of the boulder opal types and often referred to as “Koroit picture opals” because of the patterns.

Kunzite
Kunzite is a transparent pink, light pink, or light purple gemstone that resembles roze quartz. It is a variety of the mineral spodumene. Kunzite can fade after prolonged exposure to light. Kunzite is also called “evening stone,” because of its propensity to fade in bright light. The original color of some kunzite stones can be restored or even intensified by irradiation. It is usually used as a large stone and is easily chipped; small stones of kunzite are difficult to cut. Kunzite is often used in pendants. Kunzite has a hardness of 6-7 and a specific gravity of 3.1 – 3.2. Kunzite was first found in 1902 in Pala, California, USA, and is named for the gemologist George F. Kunz. Kunzite’s chemical composition is LiAlSi2O6

Kyanite
Kyanite is a deep sapphire blue, green, gray, or white gemstone. The color is not always uniform; it can be blotchy or in streaks. The cystals are crystals are transparent to translucent. Kyanite has a hardness of 4.5 to 6.5; the hardness varies depending on which way it is scratched (this happens because kyanite consists of long, thin crystals). It has a specific gravity of 3.58. Kyanite is found in Brazil, Burma, Kenya, Europe, India, Australia, Kenya, and the USA. Kyanite’s chemical composition is Al2SiO5; it is composed of andalusite and sillimanite.

Lab Ruby (Sapphire)
A lab ruby (or sapphire) is a synthetic (laboratory-made) stone. It has the same composition, hardness, and specific gravity as natural rubies (or sapphires) but is much less expensive than a natural stone (since they are relatively inexpensive to create in the laboratory as comared to mining gemstones). These lab-produced stones can be legally referred to as “real” stones [as opposed to “natural” (mined) stones].

Labradorite
Labradorite (a variety of plagioclase feldspar) is a fairly abundant grayish mineral that has brilliant flashes of color (usually green, blue or red) after it is polished (called labradorescence). The crystals are transparent to translucent. There is a darker variety of labradorite (called “black moonstone”) which has bluish inclusions. Labradorite is usually cut with a flat surface in order to highlight the flashes of color. Labradorite was originally found along the coast of Labrador about 1805; it is also found in Newfoundland, other parts of Canada, also known as spectrolite, the Ukraine, the Ural mountains, and the USA. Labradorite has a hardness of 6 to 6.5 and a specific gravity of 2.70. Finnish labradorite is also known as spectrolite.

Lampworked Glass
Lampworked glass (also called torchwork) is formed from glass canes and tubes that are shaped by hand over a flame (oil lamps and bellows were originally used, hence the name lampworking). Lampworked glass beads are made in a wide variety of colors, shapes, and designs, including millefiori, rose-like overlay beads (pictured above), aventurine glass, and many others. Lampworking was invented in the 1700’s in Murano, Italy.

Lapidary
A lapidary is someone who cuts and polishes gemstones.

Lapis Lazuli
Lapis lazuli is a rich blue opaque, semi-precious stone that has been used in jewelry since ancien times. Ground-up lapis lazuli was once used as a pigment for oil paintings. Lapis lazuli is often dyed to deepen and improve its color. Lapis has a hardness of 5.5; it chips and scratches easily. It has a specific gravity of 2.4 to 2.9. Water can dull its sheen. Lapis lazuli contains the minerals calcite (which decreases its value), pyrite (which can increase its value), and sodalite. Swiss lapis is not Lapis lazuli at all; it is dyed jasper. Denim lapis is relatively pale, low-grade, inexpensive lapis from Chile; it is the color of denim cloth because of calcite inclusions (which whiten the color and lower the value).

Lariat
A necklace without a clasp, worn looped around the neck with open ends that may be tied into a loose knot, fastened with a ring or a brooch, or tied with a “lariat loop”.

Larimar
Larimar is a form of pectolite (with copper) found only in a single place in the Dominican Republic. It is an opaque sky blue stone with white streaks. There are often some red to brown impurities. Larimar is usually shaped and polished (but not faceted). Larimar has a hardness of 4.5 – 6.0 and a specific gravity of 2.7 to 2.9. Larimar is not enhanced. Larimar was named for Larisa (the daughter of Miguel Mendez, a geologist who helped reintroduce this stone) and mar (the Spanish word for sea).

Lathe
A lathe is a machine that turns metal, wood, etc. The material to be turned is held horizontally on the machine and rotated very quickly while the jeweler applies a sharp cutting tool to the material, removing excess material, shaping the article. Rings are sometimes turned on a lathe, but most jewelers do not use lathes.

Lava
Lava from the volcano Vesuvius near Pompeii in Italy has been used to make jewelry, especially cameos. Lava jewelry was popular in the nineteenth century.

Lavalier
A lavalier is a pendant with a dangling stone that hangs from a necklace. Lavaliers were named for the infamous Duchess Louise de La Valliere (1644-1710), a French woman who was a mistress of the French king Louis XIV (and was involved in many intrigues at court).

Lead Crystal
Lead crystal is high-quality glass containing at least 10% lead oxide. Glass containing at least 24% lead oxide is called lead crystal. Glass containing at least 30% lead oxide is called full lead crystal. Lead added to the melt produces very clear glass resembling rock crystal. The process of making lead crystal was discovered by the English glassmaker George Ravenscroft in 1676. Crystal is colored by adding various metallic oxides to the melt. When cut and polished, crystal becomes quite brilliant.

Leaf
Metallic leaf is paper-thin sheets of metals. For example, gold, silver, platinum, and copper are rolled or pounded into metallic leaf which can be applied to surfaces.

Leaf
The plant leaf is a common motif in jewelry. The leaf pin pictured above was made by the Trifari jewelry company.

Leather Cord Jewelry
Jewelry strung on a thin leather cord has become popular recently. Pendants, beads, shell, feathers, and/or sharks teeth are strung on leather to make interesting necklaces and bracelets.

Lentil Cut
A lentil cut stone is a cabochon cut in which the upper and lower portions of the stone are identical.

Linde Star Sapphire
Linde star sapphire (“Linde stars”) are synthetic star sapphires that were first made by the Linde Air Products Company in 1947 (they also developed star rubies that year). The Linde company later became a division of Union Carbide. Star sapphires are sapphires that have a six-sided asterism.

Lobster Claw Clasp
A lobster claw clasp is a jewelry fastener that resembles the claw of a lobster. A tiny spring keeps the arm of this clasp closed. It is used to attach two other rings or links of a necklace or bracelet.

Locket
A locket is a pendant that can open up. Lockets can hold photos, hair, a charm, or other small, precious object.

London Blue Topaz
London blue topaz (Aluminum silicate fluoride hydroxide) is the darkest blue variety of topaz. Most blue topaz is silver topaz that has been irradiated and heat treated, but some stones are blue naturally. London blue topaz is found in Brazil, U.S.A., Sri Lanka, Myanmar (Burma), Russia, Australia (including Tasmania), Pakistan, Mexico, Japan, and Africa. Topaz has a hardness of 8 and a specific gravity of 3.5-3.6.

Lorgnettes
Lorgnettes are glasses (or opera glasses, which are small binoculars) that are mounted on a handle. This type of glasses was used a long time ago.

Lost Wax Casting
Lost wax casting is a process of casting metal in which the original model is sculpted in wax. The wax is then enclosed in clay and the wax is melted out, making a hollow mold. The mold is then filled with molten metal. The clay is broken off and the cast metal remains. This method of casting has been used for at least 4,000 years.

Lozenge
A lozenge has a diamond shape. A lozenge cut stone is a step-cut gem with a diamond shape.

Lucite
Lucite is a clear (transparent), strong plastic (a thermoset acrylic resin) that was patented by the DuPont company in 1941. Lucite has a specific gravity of 1.19. Although it is clear, it can be colored. The bangle above is made of transparent confetti lucite.

Luster
A stone’s luster is its sparkle or sheen – the way it relects light. The luster depends on the nature of the stone’s surface reflectivity. Some types of luster include: adamantine (also called brilliant or diamondlike, like a faceted diamond), earthy (with little reflectivity- also called dull, like shale or clay), greasy (like nepheline or apatite), metallic (also known as splendent, like pyrite or marcasite), resinous (like amber), pearly (with an iridescent reflectivity, like pearls or mica), pitchy (tarry minerals that are radioactive, like uraninite), silky (with a fibrous structure, like some tiger’s eye or satin spar), vitreous (also known as glassy, like olivine, transparent quartz, or obsidian), and waxy (like halite or turquoise). A pearl’s luster is derived from its nacre.

MABE’ (Or Mobe’)
A Japanese term for cultured pearls which are cultured against the shell so that only half a pearl is formed resembling a half-sphere.

Mabe Pearl
Mabe pearls are large, hemispherical cultured pearls that grow attached to the inside shells of oysters. Mabe pearls are used in earrings, pins, and rings.

Machine Stamping
Machine stamping (also known as die-stamping) is a process in which sheet metal is cut and shaped between two dies, forming a pattern in relief. Two steel dies are used, the male die has the design in cameo (protruding); the female die has the design hollowed out. The male die is put on top of the metal, the female die is put on the underside of the metal. The press is forcefully brought down onto the dies and metal, forcing the metal into the shape of the mold. Many medallions and mass-produced jewelry findings are made this way.

Magnesia
Also called periclase, magnesia is a light, solid, white earthy mineral composed of magnesium oxide. It is a source of magnesium and is used as a laxative. It takes its name from Magnesia, an ancient city of Asia Minor, and is a mineral ingredient of the philosophers’ stone.

Magnesium
A light, silvery-white, moderately hard, malleable, ductile, metallic element which only occurs in nature as a compound with other elements, as found in magnesite, spinel and olivine. In ribbon or powder form magnesium burns with a brilliant white flame, (the so-called magnesium light), which is used in signaling, pyrotechnics, incendiary bombs, or in photography where a strong actinic illuminant is required.

Mahogany Obsidian
Mahogany Obsidian (also called Apache tears) is brownish obsidian. This glassy, lustrous mineral is found in lava flows, and obsidian stones can be massive. Obsidian is formed when viscous lava (from volcanos) cools rapidly. Most obsidian is 70 percent silica. Obsidian has a hardness of 5 and a specific gravity of 2.35. The pin above is Mahogany (brown) obsidian.

Malachite
Malachite is an opaque semi-precious stone with layers of deep green and light green. It is usually found in copper mines; malachite is about 57% copper. Malachite was used as jewelry thousands of years ago by the ancients Egyptians. Malachite is usually cabochon set in silver. Russian malachite carvings were done in miniature and in large scale; malachite was also inlaid in furniture. Malachite has a hardness of 4 and a specific gravity of 3.80. It is monoclinic; it has one two-fold axis of symmetry. Malachite is sometimes coated with colorless wax, oil, or hardening agents to increase its durability and enhance its appearance.

Malleable
Malleable metals are easily worked with a hammer or a roller. gold and sterling silver are very malleable metals.

Maltese Cross
Maltese cross is a cross whose four equal-length arms get larger the farther they get from the center. The Maltese cross brooch above is by Weiss; it has red paste stones and a Japanned finish.

Mandrel
A mandrel is a metal rod used to coil molten glass in order to make a bead.

Manganese
A gray-white or silvery brittle, metallic, element which resembles iron but is not magnetic. It is found abundantly in the ores pyrolusite, manganite, and rhodochrosite and in nodules on the ocean floor. Manganese is alloyed with iron to form ferromanganese, which is used to increase strength, hardness, and wear resistance of steel.

Manganite
Steel-gray or iron-black crystals composed of manganese oxide. Used as a source of manganese.

Mabble
A metamorphic rock composed of calcium carbonate, (like aragonite or coral), or carbonate of lime, (limestone or dolomite, a variety of calcite), which is swirled or clouded with color. It is most often used for architectural and ornamental purposes. The most common variety is white, but it can also be yellow, red, or green.

Marbled
A stone, or other object, with two or more colors swirled together.

Marcasite
Marcasite is a shiny, metallic semi-precious stone. It is actually iron pyrite. Marcasite is generally faceted. The Czech guilloche pin above is studded with marcasites.

Marina chain
A chain composed of small, round, diamond cut links that are designed to lie flat like a curb link chain, but are set very close together.

Mariner Link
A chain link resembling a flat oval with a flat bar in the middle of the ring. A figogucci chain is a variant form.

Marquise
Marquise cut stones have a shape like an oval with two pointed ends.

Matinee-Length
A matinee-length necklace is a single strand that is from 22 to 23 inches (56 to 58 cm) long. Matinee-length generally refers to a string of pearls that hangs to the top of the cleavage.

Matisse
Matisse is a line of enameled copper jewelry from the “Renoir of California” jewelry company. The enameled copper leaf pin above is marked Matisse.

Matte
With jewelry which has a matte finish the designer uses either a chemical process or an abrasive material to scratch the top layers of the piece creating a dull and non-reflective surface. Also referred to as having a “brushed finish.”.

Matte Finish
A matte finish on a metal’s surface is a soft, lustrous finish that reduces the metal’s reflectivity.

Maw-Sit-Sit
Maw-sit-sit is a rare green gemstone that has dark-green to black veining; it sometimes has white spots. The stone is opaque to translucent. Maw-sit-sit has a hardness of 6.0; the specific gravity is 2.5 to 3.5. This stone is found in Maw-sit-sit, Myanmar (Burma), and is often found neat jadeite, but maw-sit-sit is not a type of jade. Maw-sit-sit was first identified in 1963 by the Swiss Gemologist Eduard Gübelin; the local called the stone maw-sit-sit, and the name was retained. Although its exact composition is still unknown, Maw-sit-sit is composed of chromite, ureyite, chrome jadeite, symplektite, chrome amphibole, and other lighter minerals.

Melanite
A common black variety of garnet composed of iron lime.

Melee
A melee is a small diamond, under .20 carat.

Memory Wire
Memory wire is a tough, stiff wire that retains its shape. It is often used for necklaces and bracelets.

Mesh
A sheet of fabric-like woven fine wire, similar to the kind used for screen doors.

Metallic
The quality used to describe a gem with a luster similar to metal. Hematite, pyrite, stibnite, silver topaz and Gibeon Meteorites are some gems which display a metallic luster.

Mexican Diamond
Mexican diamond is a misleading term for rock crystal, and not a diamond at all.

Mexican Jade
Mexican jade is a misleading term for dyed stalagmitic calcite; it is not jade.

Mifa
MFA stands for the Museum of Fine Arts in Boston, Massachusett, USA. They produce reproductions of their museum pieces (and other jewelry pieces).

Mica
Mica is a soft, lightweight, transparent mineral that cleaves into thin, elastic sheets (it has a single perfect cleavage direction). It is used for lampshades and electrical insulators. There are about 30 different types of micas, ranging in color from yellow to green to gray to violet to white to brown. Mica has a hardness of 2.5 and a specific density of about 3. Tiny mica particles give the shimmer to aventurine (goldstone).

Microcrystalline
Microcrystalline is a type of mineral structure in which the crystals are so small that they can only be seen using a microscope.

Micromosaics
Micromosaics are pictures or decorations that are made out of extremely small pieces (tiles) of stone, glass or other materials. Italian micromosaics were common souvenirs. Older examples are much more intricate, have smaller mosaic tiles, and generally have better workmanship.

Micron
A micron is a unit of length equal to 0.001 mm (millimeter).

Milanese Mesh
Milanese mesh (also known as Milanese work or Milanese chain) is a an intricate mesh made from spiral wires braided together. Milanese mesh is used to make necklaces and bracelets.

Milgrain
A raised, beaded edge on a ring done with a special engraver’s tool; resembling the edge of a coin.

Milgrain Setting
A milgrain design engraved into the edge of the metal securing a stone in place.

Milk And Honey Fffect
The milk and honey effect is one in which the apparent coloring of a stone changes (from milky to the color of honey) as the angle of the light changes. When a light is shined on the stone, one side of the stone is the color of milk and the other is the color of honey. When the light changes direction, the color effect also shifts. Cat’s-eye chrysoberyl can exhibit this milk and honey phenomenon.

Millefiori
Millefiori (meaning “thousand flowers” in Italian) is glass that is formed from multiple canes of colored glass that are fused together and cut crosswise. Millefiori glass can also be made into beads.

Millegrain
A millegrain (or millegrain setting) is a setting in which the stone is secured by tiny beads [grains] of metal or a band of metal that is decorated with tiny beads of metal.

Milling
Milling is a process in which wood or metal is cut while it either the material or the tool is spinning. Symmetrical shapes and patterns are cut into the material.

Mine Cut
Mine cut stones have a cushion-shaped girdle. This type of cut was popular in the late 1800’s.

Mineral
Any inorganic substance; i.e. anything that is not a plant or an animal.

Mineral Crystal
see Quartz.

Miracle
Miracle makes Celtic or “Scottish” jewelry, jewelry using ancient Celtic designs and stones such as agate. The Miracle pin pictured above is made with agate stones.

Mint Condition
A piece of jewelry having no signs of wear whatsoever, including no discolored stones. A piece that is in Mint Condition is in virtually the same condition as it was when it left the manufacturer. Considering that vintage jewelry is usually 50 or more years old, and that it likely has been worn, it is obviously quite rare to find a piece that is truly in Mint Condition.

Mixed Cut
A mixed cut in one in which the style of the facets above and below the girdle are different. A standard mixed cut is brilliant cut above and step cut below.

Mogul Emerald
These Indian emeralds were owned by Indian moguls (like Shah Jahan, the builder of the Taj Mahal) and were inscribed with sacred blessings.

Mohs Scale
The Mohs Scale of Hardness measures a substance’s hardness, that is, how resistant it is to being scratched. In the Mohs scale, which ranges from 1 to 10, one substance is harder than another if it can scratch it. For example, a diamond (hardness = 10) will scratch garnet (hardness = 6.5-7.5), but not the other way around, so a diamond is harder than garnet. This scale was invented by Austrian mineralogist Friedrich Mohs (1773-1839).

Moissanite
Moissanite is a very hard mineral that was discovered by Dr. Ferdinand Henri Moissan (1852-1907), a French chemist and Nobel Prize winner (Moissan did work on synthesizing diamonds and discovered carborundum in 1891). He found tiny amounts of Moissanite in the iron meteorite that was found at Diablo Canyon (also called Meteor Crater) in Arizona, USA. Moissanite ranges in color from colorless to blue to green to yellow. Its chemical makeup is Silicon Carbide (SiC); it is also called Carborundum. Moisannite crystals are transparent to translucent. Moissanite has a hardness of 9.25 (this is almost as hard as diamond) and a specific gravity of 3.1 – 3.2. Laboratory-grown Moissanite is sold as a gemstone.

Mokume-Gane
A Japanese metal-smithing technique which results in a wood-like finish. Alternating layers of thin, colored metals are laminated together. Patterns are punched in the laminate, filed away or hammered. This technique produces unique and delicate patterns.

Moldavite
Moldavite is a rare, glassy, translucent, dark green gemstone. Moldavite is a silica-based tektite, a mineral formed when a meteorite (a rock from space) struck the Earth’s surface and melted and fused the surrounding rock. Moldavite is only found in Bohemia (the Czech Republic) in the Ries Crater in the Moldau River valley (which it was named for). Moldavite was discovered in the late 1800’s; the meteorite from which it formed hit the Earth about 14.7 million years ago. Moldavite has a hardness of 5.5-6.6. Inclusions of gas bubbles and iron/nickel spherules are common. This natural glass has been used for jewelry, religious articles, and decorative objects since prehistoric times.

Molded Cameos
Molded cameos are cameos that are made by the molding process and not by carving the material (as traditional cameos are). Molded cameos are usually made from plastic, glass, or porcelain that is formed in a mold. Often, two colors of material are used, one for the relief pattern (often depicting a person or scene) and another for the background. The molded cameo above is a Jasper ware porcelain cameo made by the Wedgewood Company.

Mollusk
An invertebrate animal usually enclosed in a shell, such as an oyster, mussel or clam.

Monoclinic
Monoclinic minerals have a crystalline structure in which there is one two-fold axis of symmetry. Jade, Malachite and moonstone are monoclinic.

Montana Ruby
A “Montana ruby” is actually a pyrope garnet (and not a ruby at all).

Moonstone
Moonstone (orthoclase) is a semi-translucent stone that is made of albite and orthoclase feldspar. It is usually whitish-blue, but can be colorless, yellow, orange, gray, or even reddish. Moonstone is usually set as a cabochon. Moonstone was very popular early in the 20th century and was extensively used in Art Nouveau jewelry. Moonstone has a hardness of 6 and a specific gravity of 2.57. It is monoclinic; it has one two-fold axis of symmetry. Adularia is a common type of moonstone. Oligoclase is another type of moonstone; Labradorite and albite are rare forms.

Morganite
A transparent to translucent pink gemstone. It is a variety of beryl, Be3Al2(Si6O18) that contains some manganese (giving the stone its pink color). Morganite has a hardness of 7.5 – 8 and a specific gravity of 2.71 – 2.90. It has poor cleavage and is brittle. Morganite is often heat treated to give the stone a purer pink color (and remove any yellow spots). Morganite was named for J. Pierpoint Morgan, the American industrialist and gem collector. Morganite is found in Brazil, Madagascar, Italy, Pakistan, Mozambique, Namibia, Zimbabwe, and the USA (California, Maine, Connecticut, and North Carolina).

Morse
A clasp used by the clergy for fastening garments, such as a cape, in front. It is usually very large, from 12.5 to 17.5 cm in diameter, of various materials and shapes, and decorated in religious themes.

Mosaics
Mosaics are pictures or decorations that are made out of small pieces (tiles) of stone, glass or other materials. Italian mosaics were common souvenirs. Older examples are much more intricate, have smaller mosaic tiles, and generally have better workmanship.

Moss Agate
Moss agate (also called Mocha stone in Britain and the USA) is a green variety of agate. It is chalcedony that has dendritic (tree-like) inclusions of green (red or black) hornblende. The inclusions often form beautiful patterns. Moss agate has a hardness of 6.5-7 and a specific gravity of 2.6. Green moss agate is found in India, and some other locations.

Mother-Of-Pearl
Mother-of-pearl is the iridescent coating on the inside of oyster shells. Mother-of-pearl is used for jewelry, buttons, and other uses.

Mother’s Rings
A kind of “family jewelry”, Mother’s rings are rings personalized with their children’s birthstones or with birthstones and names.

Moukaite
Moukaite is a semi-precious gemstone, a variety of jasper from Australia. The color of moukaite varies from red-browns to pinks, with gold and white bands.

Mount
To place or fix a stone in the setting. See Mounting.

Mounting
A piece of metal that holds a gem in place.

Mourning Jewelry
Mourning jewelry is a type of jewelry worn when one is mourning the loss of a loved one. It is often black, subdued jewelry (often made of jet or black glass and metal with a Japanned finish) or jewelry that commemorates the dead (like hair jewelry or cameos). After England’s Queen Victoria’s beloved husband (and cousin) Albert died (in 1861), she went into an extended period of mourning. During these years, she wore black clothing and mourning jewelry. English fashion was greatly influenced by this, and mourning jewelry, especially jet, became quite fashionable.

Muff Chain
A long chain with a clasp used to suspend a lady’s fur muff.

Mya Yay
Mya yay is the Burmese (Myanmar) name for the highest quality translucent jadeite.

Mystic Fire
Mystic fire (also called mystic topaz or rainbow topaz) is topaz that has been color enhanced by coating it with a fine layer of metal atoms (in a process called vacuum deposition). This stone has red, green, violet, and blue streaks. Mystic fire has a hardness of 8.

Nacre
Nacre is a usually whitish crystalline substance which oysters, mussels, snails, and other mollusks secrete around a foreign object (like a tiny stone) that has made its way into their shell. As layers of nacre coat the intruder, a pearl is formed over a period of many years.

Naja
(or “Najah”) From the Navajo word “Najahe”, meaning “crescent”. A crescent-shaped silver ornament believed to go back to Moorish designs that was originally a forehead pendant on horse bridles. It is now commonly found pendant from the bottom of a squash blossom necklace.

Natural Pearl
A natural pearl (also called a genuine pearl) is a pearl that was produced in an oyster, freshwater mussel or other mollusk as a reaction to a tiny invading object that happened to be caught inside its shell.

Navette
A navette is a gemstone which is cut as a marquise.

Necessaire
Necessaire is another word for etui, a tiny, decorative, cylindrical-shaped case that was often carried on a chatelaine. The necessaire/etui was used to carry small “necessary” items like pencils and scissors. The etui was first used in the 1720’s.

Necklace
A necklace is a peice of jewelry worn around the neck. Necklaces of perals of different lengths have different names: A choker is 14″ to 16″ long; a princess necklace is 18″ long; a matinee necklace is 22″ to 23″ long; opera is 30″ to 35″ long; a rope is over 40 ” long.

Needle Point
Stones shaped to a fine point at both ends.

Neoclassical
New designs inspired by artistic elements from classical antiquity, such as urns, garlands, greek key, palmette.

Nepal Diamond
Nepal diamond is a huge flawless, pendeloque diamond that probably came from the Golconda mines in India. The Nepal diamond weighs 80 carats. It was originally owned by the Nepalese government but is now owned by Harry Winston, an American jeweler.

Nephrite
Nephrite is a semi-precious stone, a variety of jade (sometimes called greenstone). Two different minerals are known as jade, jadeite and nephrite. Nephrite is slightly softer that jadeite and is often veined; it is used in carvings and for making beautiful bowls and vases.

Nevada Diamond
Nevada diamond is a misleading term for artificially-colored obsidian (a semi-precious stone) – it is not a true diamond.

Nevada Topaz
Nevada topaz is a misleading term for obsidian (a semi-precious stone) – it is not a true topaz.

Nickel
A hard, bright, silver-white metallic element of the iron group that is malleable, ductile, and resistant to corrosion.

Nickel Silver
Nickel silver (also know as German silver) is an alloy consisting of mostly copper (roughly 60 percent), and approximately 20 percent nickel, about 20 percent zinc, and sometimes about 5 percent tin (then the alloy is called alpaca). There is no silver at all in German/nickle silver. This alloy was invented around 1860 in Germany as a silver substitute.

Niello
Niello is ancient technique in which an engraved design in metal is filled with powdered niello alloy (a black/dark gray metal alloy composed of silver, copper, lead, and sulphur). The niello alloy is melted (the entire metal piece is heated in a kiln) and it fuses with the underlying metal. The object is then polished – the result is an enamel-like effect. Niello has been made at least since the time of ancient Rome. In older pieces, the niello alloy fills an engraved design in metal. In newer pieces, the nilello forms the backround – the niello alloy is simply “painted” onto the metal (this process is simpler, cheaper, and less durable).

Night Emerald
Night emerald is a misleading term for peridot (a semi-precious stone) – it is not a true emerald.

Nizam Diamond
The Nizam diamond was a huge Indian diamond that may have weighed from 340 to 440 carats uncut. After being cut into an elongated, convex shape with irregular facets, it was 277 carats. This diamond was owned by the Nizams of Hyderabad in the 1830’s. This diamond was “lost” or broken up during a battle.

Noble Metals
The noble metals are gold, platinum, and silver. These are metals that are relatively impervious to chemical action.

Nonmetallic
A material which is not composed of metal.

Non-Precious
Any metal that is not considered to be a precious metal or any gemstone that is not considered to be a precious gemstone.

Nose Stud
A simple style of jewelry for pierced nostrils that has a single stone, pearl, or metal ball on a straight post.

Nugget
The term used for a lump, or irregularly shaped mass, of precious metal.

Obsidian
Obsidian (also called Apache tears) is a volcanic glass that is usually black, but is occasionally red, brown, gray, green (rare), dark with “snowflakes,” or even clear. This glassy, lustrous mineral is found in lava flows, and obsidian stones can be massive. Obsidian is formed when viscous lava (from volcanos) cools rapidly. Most obsidian is 70 percent silica. Obsidian has a hardness of 5 and a specific gravity of 2.35. The pin above is Mahogany (brown) obsidian.

Oiling
Oiling is a process of applying mineral oil to a stone in order to enhance it and mask inclusions, make them more transparent, and darken their color. Emeralds are frequently oiled to mask their many inclusions.

Old Mine Cut
Old mine cut is a term that refers to a brilliant cut in which the stone is cushion-shaped and has a high crown (the upper part of a gemstone).

Old Rock Turquois
Old rock turquoise is an old Persian (Iranian) turquoise term for very high quality turquoise (sky blue, veinless turquoise that retains it color).

Olive
Olive is a term that refers to a bead that is olive shaped (elongated). This term is mostly used in the USA.

Onyx
Onyx is a semi-precious stone that is black and white, generally arranged in layers. It is a form of agate with parallel banding. This structure lends itself to cameo making. Onyx is a species of chalcedony (microcrystalline quartz).

Opals
Opals are semi-precious stones that are luminous and iridescent, frequently with inclusions of many colors (“fire”). Opal is a mineral composed of noncrystalline (amorphous) silica (and some water) and is a species of quartz. There are three major types of opals: common opal, opalescent precious opal (white or black, with a rainbow-like iridescence caused by tiny crystals of cristobalite), and fire opal (a milky stone that is fiery orange to red in color with no opalescence). Contra luz opals are transparent opals that show a brilliant play of iridescence only when light shines through the stone. Many opals have a high water content – they can dry out and crack if they are not cared for well (opals should be stored in damp cotton wool). Some opals are treated with oil, wax or resin to enhance their finish. Opals have a hardness of 5.5 to 6.5 and a specific gravity of 1.98-2.50. Opals are found in many places worldwide, including Kenya, Czechoslovakia, Brazil, Peru, Honduras, Mexico, Canada, and the USA — but Australia has a tremendous variety of beautiful opals.

Opal Doublet
An opal doublet is a manufactured stone that is composed of two thin layers that are glued together. A thin layer of opal is glued on top of another mineral (usually a black onyx or ironstone, which enhances the stone’s color), producing a stone that is less expensive than a solid opal. Doublets must be cleaned very carefully

Opalescence
Opalescence is a milky white/blue type of iridescence.

Opal Glass
Opal glass is a milky white glass that mimics opals.

Opal Triplet
An opal triplet is a manufactured stone that is composed of three thin layers that are glued together. A thin layer of opal is sandwiched between a layer of clear quartz and a layer of either obsidian or ironstone. The clear quartz is the top layer, making the gem harder (and less susceptible to scratches). An opal triplet is an opal doublet with a quartz layer on top. Triplets must be cleaned very carefully.

Opaque
Opaque means blocking the passage of light (as opposed to translucent or transparent).

Open-Ended Necklace
An open-ended necklace has no clasp; it is worn by tying the ends together around the neck. Open-ended necklaces usually have ornaments, like beads or tassels, at the ends.

Opera-Length
An opera-length necklace is a single strand that is from 30 to 35 inches (60 to 90 cm) long. Opera-length generally refers to a string of pearls that hangs to the breastbone.

Operculum
The operculum is part of many shelled animals – it is the calcified, disc-shaped “trap door” that opens and closes to protect the animal inside its shell. The operculum from a species of sea snail called the Turban Shell (Turbo petholatus, found in the South Seas north of Australia) is eye-like with a natural cabochon shape and is used in jewelry. This jewelry was popular in Victorian Era Britain. Operculum is also called Pacific Cat’s-eye.

Ormolu
Ormolu (meaning “ground gold” in French) is an alloy of the metals copper, tin and zinc that is used to imitate gold. Ormolu can also be cast bronze or brass that is plated (gilded) with a gold and mercury amalgam, giving it a gold-like look. Ormolu is used in frames, chandeliers, candlesticks, and furniture ornamentation. It was very popular in Georgian and early Victorian design. Ormulu can now also refer to any gold-like metal used as decoration. Ormolu is also called bronze doré or mosaic gold.

Ouro Verde
Ouro verde (meaning “green gold” in Portuguese) is a type of quartz crystal found in Brazil. This transparent stone is always irradiated (to give it its pale, golden-green color).

Oxidation
Oxidation is a chemical process in which oxygen atoms bond to atoms of a material (like a metal) and electrons are transferred from the oxided material to the reduced material. Iron oxidizes when exposed to air and moisture, forming iron oxide (rust). Silver oxidizes (tarnishes, turing the surface black) when it is exposed to hydrogen sulfide in the air (forming Ag2S, silver sulfide).

Pacific Cat’s Eye
Pacific Cat’s-eye is the operculum of a sea snail called the Turban Shell (Turbo petholatus, found in the South Seas north of Australia). The operculum is part of many shelled animals – it is the calcified, disc-shaped “trap door” that opens and closes to protect the animal inside its shell. The Turban Shell’s operculum is an eye-like disc with a natural cabochon shape – it is used in jewelry. This jewelry was popular in Victorian Era Britain.

Padparadscha Sapphire
Padparadscha sapphires (also spelled padparadschah) are a rare pink-orange variety of corundum or the synthetic equivalent. These gems are mined in Sri Lanka and are usually heat treated to improve and intensify the color. The name padparadscha comes from the Sinhalese word for lotus flower. Hardness = 9, Specific Gravity = 4.

Palatte
A palette is a board which artists apply paint to when they are preparing to make a painting. In regards to any medium outside of painting, the palette simply refers to the group of colors chosen by a particular factory or decorator.

Palladium
Palladium is a valuable, durable, and malleable light-gray metal used in some jewelry; it is related to platinum, but is less dense and has a lower melting point. Unlike platinum, palladium reacts when exposed to aqua regia, sulfuric, nitric, and hydrochloric acids. It also develops a tarnish when it is heated. Pallasium is not a shiny as platinum. Palladium was only isolated as an element in 1802 by William Hyde Wollaston and Smithson Tennant. It was first used in jewelry in 1939 (during World War 2, platinum was used for war purposes, and was not available for jewelry making – palladium was temporarily used as a substitute for platinum). White gold is sometimes alloyed with palladium (instead of nickel), resulting in a gray-white gold. After World War 2,palladium was rarely used in jewelry making beacuse of some difficulties in working with it. Palladium was recently discovered to be useful in engine catalytic converters, and its price skyrocketed to over $700 per ounce (it had previously been much less expensive than platinum or gold) and is no longer practical to use as jewelry.

Palamette
A stylized palm leaf which is a common motif in Greek and Persian art.

Palmwood
The characteristic spotted look of palmwood is from the rod like structures found within the grain of the original wood. Depending upon the angle the lapidary uses to cut the stone, these structures show up as spots, tapering rods, or lines. Petrified palm wood is very hard, a 7.5 on the Mohs scale and ranges in color from black, light beige, yellowish-brown and brown.

Paper Roule
A paper roule is a bead made by rolling up paper (usually triangles).

Parure
A parure (meaning “personal adornment” in French) is a matching set of jewelry, usually containing a necklace, earrings, brooch and a bracelet (or two bracelets). See demi-parure.

Paste
Paste is glass that is cut and faceted to imitate gemstones. The Trifari set above has high quality paste emeralds, rubies and sapphires.

Pastille Burners
A form of incense burners popular from 1820-1850 in the form of cottages, churches, or summer houses, with detachable lids.

Pate De Verre
Pate de verre (also known as glass paste) is glass that is ground into a paste, molded, and then melted. The final piece is an opaque, dense glass with a frosted surface.

Patina
Patina is the change of an object’s surface layer that result from aging. Exposure to the air for an extended period of time oxidizes many metals, turning copper and bronze green, and gold reddish. Artificial patinas can be applied to newer objects by using acids or electrolytes.

Pave
Pav? settings are stones set very close together. The stones hide the underlying surface. In better pieces, claw settings are used; in less expensive pieces, the stones are simple glued in.

Pavilion
The pavilion is the lower part of a cut gemstone, below the girdle.

Pavilion Height
The distance from the girdle to the culet of a cut gemstone.

Peacock Pearl
Peacock pearls are a type of black pearls that are dark-green (almost black). These pearls (like all black pearls) are produced by the oyster Pinctada margaritifera.

Pear Cut
A pear cut gemstone (also called a drop cut) is teardrop shaped This type of cut is used for pendants, drop earrings, rings, and other pieces of jewelry.

Pearl
Pearls are organic gems grown within oysters and a few other mollusks. Pearls are formed when a foreign object (like a tiny stone) has made its way into the mollusk’s shell. The mollusk secretes nacre, a lustrous substance that coats the intruding object. As thousands of layers of nacre coat the intruder, a pearl is formed; this process takes up to seven or eight years (an oyster’s useful life span). The most valuable pearls are perfectly symmetrical, large, naturally produced, and have a shimmering iridescence (called orient luster). There are many types of pearls, including natural pearls (made with no human interference), cultured pearls (pearls made by inserting a bit of a mother-of-pearl) into [nucleating] a living oyster or by inserting a bit of foreign tissue), baroque pearls (irregularly-shaped pearls), freshwater pearls, seed pearls (tiny pearls), Biwa pearls (a type of freshwater pearl from Lake Biwa, Japan from the freshwater mussel, Hyriopsis schlegeli), blister pearls (grown attached to the shell), black pearls (gray to black pearls), Mabe pearls (cultivated blister pearls), etc. Pearls can be gently cleaned with mild soap and water. The biggest natural pearl, known as the “Pearl of Allah” or “Pearl of Lao-tse,” weighs 14 pounds (6.4 kg).

Pearlescent
A term used to describe a surface with lustrous cloudy rainbow-like colors like one might see in an oil slick or mother of pearl. Synonymous with Iridescent

Pearl of Allah or Pearl of Lao-Tse
The biggest natural pearl, known as the “Pearl of Allah” and later, the “Pearl of Lao-tze,” was found off the Phillipine island of Palawan in 1934. It weighs 14 pounds (6.4 kg). It was formed inside a giant clam, Tridacna gigas, the only mollusk big enough to create such a giant.

Pearl Opal
Pearl opal (also called Tabasheer or tabashir opal) is an organic stone that forms in damaged joints (nodes) of bamboo plants. This hydrated form of silica appears as a rounded mass of opal, and looks like seed pearls.

Pearly
The term used to describe the surface of a gemstone which exhibits a luster similar to that of a pearl or mica.

Peking Glass
Peking (Beijing) glass was first made in China in the late 1600’s, during the Quing Dynasty, when a German priest introduced glass -making techniques to he Imperial court. Early Peking glass was made to imitate porcelain (it often has a translucent, milky sheen). Later (after 1725), an overlay technique was developed in which two (or more) layers of glass are fused together, and then the upper layer(s) are partially carved away, creating a multi-colored bas relief (similar to a cameo). Peking glass and overlay glass is used for vases, bowls, dishes, beads, snuff bottles, and other objects. Peking glass is still made, but is now manufactured in Poshan, China, and shipped to Peking for final finishing.

Peking Jade
Peking jade is the same as jade, but often refers to nephrite.

Penannular Brooch
Penannular brooches are a type of early Celtic jewelry. They are circular brooches with a long pin (oftern hinged to the base of the pin). These pins were used to fasten two pieces of cloth together (before buttons were invented). The earliest-known piece is the Hunterston brooch from A.D. 700

Pendant
A pendant is a hanging ornament. Necklaces, pins, and earrings often have a pendant. The Christian Dior pendant shown above is costume jewelry.

Pendelique
A pendelique cut in one that is lozenge shaped. This cut is frequently used for flawed stones. Pendelique cut stones are often used as pendants.

Quadrillion Cut
A Quadrillion cut is a square-cut stone. This fancy cut is relatively new and is also known as a Princess or Squarillion cut.

Quartz
Quartz is a crystalline mineral that come in many forms, including amethyst, aventurine, citrin, opal, rock crystal, tiger’s eye, rose quartz,and many others. Rutilated quartz and tourmalinated quartz have needle-like inclusions of other minerals. Quartz has a hardness of 7.0. This common mineral is found worldwide.

QUARTZITE
A hard rock made of interlocking quartz crystals formed when sandstone has been subjected to intense heat and pressure.

Quartz Druze
Quartz druze is a layer of quartz crystals that form within a mineral crust, like the inner cavity of a geode. For example, the inner cavity of agate geodes are often lined with a druze of sparkling quartz crystals.

Quinzite Opal
Quinzite opal is a red to pink type of opal. This opal is also called Quincite, Quincite Opal, and Rose Opal.

Radiant Cut
The radiant cut is a method of cutting rectangular stones so that they have the sparkle of brilliant cut round stones. The shape is a rectangle with the corners clipped off – the length:width ratio is usually from 1.5:1 to 1.75:1. This cut has from 58-70 facets; it was invented in the 1970’s. The top of the stone is emerald cut (with about 25 facets above the girdle), but the bottom of the stone has brilliant cut facets (with about 36 facets below the girdle).

Rainbow Calsilica
Rainbow calsilica is a newly-found, multi-colored, layered stone composed of calcium and silica. This stone has been recently used for Zuni fetish carvings and in some jewelry (beads and cabochon cut stones). Rainbow calsilica was only recently found in Mexico or Northern South America (it’s origin remains mysterious). Some people theorize that this stone formed as a result of the runoff of mining or oil-drilling chemicals, and has only formed in the last 30 to 50 years (but this is uncertain).

Rainbow Obsidian
Rainbow obsidian is another name for obsidian that is iridescent.

Rainbow Opal
Rainbow opal is a type of precious opal that has curved bands of colors (that resemble rainbows).

Rainbow Topaz
Rainbow topaz (also called mystic topaz or mystic fire) is topaz that has been color enhanced by coating it with a fine layer of metal atoms (in a process called vacuum deposition). This stone has red, green, violet, and blue streaks. Mystic fire has a hardness of 8.

Rajaratna
The Rajaratna is the biggest-known “star ruby” (a ruby that exhibits an asterism, a six-pointed star of light, cut as a cabochon). It weighs 2,475 carats.

Ratchet Bezel
A bezel that can turn clockwise or counterclockwise and clicks with a ratchet action as it rotates.

Rati
The rati is an Indian unit of weight that is used for gemstones. A rati is equal to 0.91 carats. The rati has varied in the past (and in different regions).

Raviratna
The Raviratna is the biggest-known ruby. It weighs 3,600 carats.

Razza
Razza is a line of costume jewelry from the 1960s and early 1970s designed by Luke Razza. Razza’s pieces are highly collectible; they are mostly figural (often depicting animals and signs of the zodiac) and are generally large in scale. Many Razza pieces incorporate plastic with the metal.

Reconstituted
This is a term applied to stones which are made by using small chips, powder and ground up low grade stones, binding or fusing them with a plastic resin (epoxy) and compressing them into blocks. The blocks are then cut into beads, cabochons, and slabs.
In some cases, the reconstituted stone is actually made from “real” turquoise, amber, lapis or similar stone, but often the reconstituted stones are nothing more than low grade rocks, like howlite, that have been dyed and compressed to look like the real gemstone.
Ambroid is a form of reconstituted amber made from real amber pieces, but is should be
classified as imitation because of the epoxy resin content. It is made from scraps and shavings of amber that are heated and pressed into large blocks. Insects found in ambroid are usually fully intact, without broken body parts, as they were dead when added to the block. Insects found in real amber usually have broken wings and legs caused when they tried to escape from the sticky tree resin.
Reconstituted turquoise is manmade from pulverized pieces of turquoise that are stabilized and compressed with plastic resins to which dye is added and should be sold as “simulated” or “imitation” turquoise. However, this form is often used in much of the mass produced inlay jewelry.

Reconstructed Stone
A reconstructed stone is one that is made from pieces of smaller stones or crystals). Reconstructed stones often have telltale air bubbles. For example, “Geneva rubies” (reconstructed rubies) are made from tiny ruby crystals that have been fused together. This type of stone is generally no longer manufactured (except reconstructed amber, which is stilll made) because synthetic stones are vastly superior to reconstructed stones.

Red Beryl
Red beryl is a is a rare, deep red variety of beryl. Gemstone-quality forms of this mineral are found in only one place in the world, in the Wah Wah Mountains, near Beaver, Utah, USA. Small crystals of this gem were first found in 1905 in the Thomas Range in Juab County, Utah. The mine bearing gemstone-quality red-beryl was found in the 1950’s. The biggest red beryl crystal ever found was 14mm by 34mm, weighing about 54 carats. The average faceted red beryl gemstone weighs about 0.15 carats. Red beryl has a hardness of 7 – 8, a specific gravity of 2.66-2.70, and a refractive index of 1.564-1.574. The chemical formula Be3Al2SiO6, with other trace elements. Internal flaws in beryl gems can be hidden by treating the stone with oil (this is often not disclosed to the buyer).

Red Diamonds
Red diamonds are rare, fancy diamonds and are quite valuable. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known. Diamonds have a hardness of 10, a specific gravity of 3.5, and a refractive index of 2.417 – 2.419.

Red Gold
See Rose Gold.

Red Jasper
An opaque, rust-red color of jasper.

Refraction
When light enters a medium with a different optical density (like a gemstone), the light is bent at an angle (and also changes its speed).

Refractive Index
The refractive index is a measure of how light is refracted in a substance (like a gemstone). In doubly-refractive stones, the light is split into two light rays when it enters the stone, and the rays travel in different paths – so these stones have more than one refractive index.

Refractometer
A refractometer is a device that measures the refractive index of a gemstone.

Refractory
A material with a high melting point, which makes it useful as a barrier between the heat source and a material that you don’t want to melt, like the sides of an oven, etc..

Regard
Regard jewelry uses the stones Ruby, Emerald, Garnet, Amethyst, Ruby, and Diamond to spell the word “REGARD.” Regard jewelry was given as a token of affection. This sentimental style was popular during the Victorian era.

Relief
A kind of decoration that protrudes from the surface, like a cameo.

Rebaussabce
The period in western Europe from the mid fifteenth century to the industrial age. The word means “rebirth” and was characterized by a radical development in the arts, medicine, politics and sciences.

Repousse
Repousse is a method of decorating sheet metal in which designs are hammered into the back of the metal. Special punches are used to form the designs, which form in relief (raised designs) on the surface of the metal.

Resinous
A type of luster exhibited on gemstones like amber.

Reticulation
Used in the jewelry making process to create a textured surface with ridges, ripples and valleys. The process requires deft use of a torch to bring the metal to a high
temperature just below its actual melting point. The jeweler carefully moves the torch flame around the metal surface, “pulling” the almost flowing metal into various ridges.
This takes extreme concentration and patience, allowing the torch to remain directed in one area for a split second too long will cause the metal to melt and either form a hole or a “ball” of molten metal instead of realizing the desired effect. The pattern of valleys and ridges of a reticulated piece is unpredictable and trying to duplicate a pattern is impossible although a skillful craftsperson will be able to create something similar for perhaps an earring set.

Retro
Retro jewelry is chunky, geometric jewelry from the 1940’s. Pink gold was often used in retro pieces.

Reverse Crystal Jewelry
(also called Essex crystal) A clear crystal is cut as a cabochon. A carving is made on the flat side, like an intaglio, and painted with a thin layer of mother of pearl to produce a three-dimensional effect.

Reverse-carved lucite
Reverse-carved lucite is lucite (a transparent plastic) that is carved on the back side. The incised areas are often painted, highlighting the carving. The pin pictured above is clear, reverse-carved lucite that is accentuated with yellow and green paint; the painted carving closely resembles tiny roses.

Rhinestones
Rhinestones are highly reflective glass made to imitate gemstones. The original rhinestones were quartz stones (rock crystal) obtained from the Rhine river. These stones were cut to resemble gemstones. The best rhinestones today are made of highly reflective leaded glass which is faceted and polished. The Trifari pin above has baguette cut and round cut rhinestones.

Rhodium
Rhodium is a white precious metal. Rhodium is extremely expensive and is often used to plate precious and base metals, giving jewelry a hard, platinum-like sheen.

Rhodochrosite
Rhodochrosite is a mineral whose color ranges from rose to pink to almost yellow or brown. Although it is very pretty, this stone is soft and brittle; it is used in jewelry and for carvings and figurines. Rhodochrosite is Manganese Carbonate; its chemical formula is MnCO3. Rhodochrosite has a hardness of 3.5 – 4.5 (glass has a hardness of 4) and a specific gravity of 3.5. Rhodochrosite is found in Argentina, Peru, Germany, Mexico, South Africa, Russia, Italy, USA (Colorado and Montana), and Romania. Rhodochrosite is not enhanced.

Rhodolite
Rhodolite (meaning “rose stone” in Greek) is a purple-red to pink-red variety of garnet. It is a combination of almandine and pyrope (it is sometimes called pyrope-almandine garnet). This silicate stone has a hardness of 7-7.5 and a specific gravity of 3.5 – 4.3. The formula for garnet is: A3B2(SiO4)3. Rhodolite is found in the US, Zimbabwe, Kenya, and Sri Lanka (Ceylon). Rhodolite is not enhanced.

Rhodonite
a glassy, opaque, pink to rose-red mineral, often with black inclusions, composed of crystalline manganese silicate. Named after the Greek word “rhodon” meaning “rose”. It is found in the former Soviet Union, the U.S., India, and Australia and is usually used as an ornamental stone.

Rhombohedral
Resembling a prism with six four-sided facets.

Ribbed
An undulating ridged texture, like a person’s rib cage showing through the skin.

Ring
A ring is a piece of jewelry worn around the finger; rings have been worn on every finger, including the thumb. Rings have been worn through the ages, and often have significant meaning. Some rings include wedding and engagement rings (denoting commitment), signet rings (impressed with the owner’s seal), bands (made from a ribbon of metal), rings denoting group membership (like Masonic rings or college rings), devotional rings (with religous meaning), and pugilist rings (pointed rings worn by boxers to harm their opponent).

Ring Guard
A ring worn above another ring to keep it from slipping off the finger.

Rings Sized
Rings are sized using a graduated cone (a mandrel) with markings denoting the ring sizes. The ring is put on the cone and its size is read where it fits snugly on the cone. To size a finger, a finger-ring gauge is used. The rings are marked with their size and the person determines which one fits well. Another, less accurate method, is a cardboard card with cut-out holes marked with the ring sizes. Sizes in the US and Europe are numerical; sizes in the UK are alphabetical. To determine the ring size of a finger using the circumference of the finger, or to determine the size of a ring given its diameter, the formulas are:
System Formula using Circumference Formula using Diameter
USA Circumference in mm = 36.107 + (2.5890*Ring Size) Diameter in mm = 11.4931 + (0.8241*Ring Size)
Europe Ring Size =Circumference in mm Ring Size = 3.1416 * Diameter in mm
UK Circumference in mm = 36.667 + 1.2368*Ring Size(where 1=A, 2=B, etc.) Diameter in mm = 11.6713 + [0.3937 * Ring Size(where 1=A, 2=B, etc.)]

Riveting
A method of joining two flat objects together by making a hole in each piece, then passing a pin with a large flat head, (composed of the same metal as the piece), through the holes. The pin is then pounded flat to secure it in place. This process was used in jewelry instead of soldering when it was not advisable to use heat or when one part was intended to swivel.

Riverstones
Riverstones are smooth, rounded pebbles found in rivers and on beaches. The action of the water and other rocks on riverstones polishes them naturally. Riverstones can be used as beads/stones in jewelry.

Riviere
A necklace composed of a single strand of gemstones of the same size and cut, usually Diamonds.

Rocaille
Rocaille is jewelry whose design is based on sea life, sea shells, or rocks.

Rock Crystal
Rock crystal is a transparent, crystalline mineral. Rock crystal is the purest form of quartz and a semi-precious stone.

Rocky Mountain Ruby
A Rocky Mountain ruby is actually a pyrope garnet (and not a ruby at all).

Rolled Gold
Rolled gold is a very thin sheet of gold that is laminated to a lesser metal (usually brass). The two layers of metal are heated under pressure to fuse them together. The sheet is them rolled into a very thin sheet and then used to make jewelry or other objects. Jewelry made from rolled gold wear well over time. Rolled gold pieces are marked rolled gold plate, R.G.P., or plaqué d’or laminé.

Rolo Link Chain
A chain composed of individually linked round or oval rings resembling a standard cable chain, but with thicker rings.

Rondella
A round metal disk, sometimes studded with stones, that is strung on a necklace as a spacer between beads.

Rondelle
A rondelle is a small disc used as a spacer in beadwork. Some rondelles are clear crystal discs, often used between colored crystal beads. Other rondelles are encircled with chanel-set diamonds or rhinestones.

Rope
A rope is a string of pearlsthat is over 40 inches long.

Rope Chain
A series of small oval-shaped links that are arranged in such a way that they make a spiral design resembling woven rope.

Rose de France
Rose de France is a recent name for a very pale variety of amethyst. It is also known as lavender amethyst. Rose de France has a hardness of 7.0. This pale lilac transparent gem is found worldwide and is a type of quartz. Rose de France is sometimes heat-treated in order to lighten its color and/or to remove smokiness.

Rose Cut
The rose cut (also called the rosette cut) for diamonds was invented in the 17th century and its used continued until the 18th century. The rose cut has a flat base and triangular facets (usually 24). This cut has little wastage of stone, but is not nearly as reflective as the brilliant cut, which was invented later.

Rose Finish
Jewelry finished so that it has the look of Rose Gold, but no actual gold content.

Rose Gold
Rose gold (also known as pink gold) is gold with a pink tinge. It has been alloyed with a mix of 90% copper and 10% silver.

Rose Quartz
Rose quartz is a form of quartz that ranges in color from pink to deep red.

Rotating Bezel
A bezel that can be turned to perform different timekeeping and mathematical functions.

Rotational Axis
See Axis of Symmetry.

Rough
Rough stones or crystals are in their natural state, they are neither cut nor polished.

Roulz
Roulz is a metal alloy that consists of about copper, nickel, and silver. Ruolz is named for the French chemist and musician Vicomte Henri de Roulz, who invented the alloy in the 1800s.

Round Brilliant Cut
See Brilliant cut.

Rubellite
Rubellite (sometimes spelled rubelite) is a red variety of tourmaline. Rubellite is red in both incandescent light and daylight, and is more valuable than other varieties of red tourmaline. Rubellite has a hardness of 7-7.5 and a specific gravity of 3.02-3.25. Rubellite is sometimes treated with fillers to increase the clarity of the stone.

Ruby
Rubies are precious stones and a member of the corundum family (Al2O3). Rubies range in color from the classic deep red to pink to purple to brown. Rubies are extremely hard; only diamonds are harder. During the renaissance, people thought that rubies could counteract poison. Laboratory-produced rubies were created in the 1890’s; they are difficult to distinguish from natural rubies. The biggest ruby in the word is the Raviratna, which weighs 3,600 carats. Rubies have a hardness of 9 and a specific gravity of 3.9 – 4.1. Rubies are found in Afghanistan, Australia, Brazil, Cambodia, India, Myanmar (Burma), Malagasy Republic, Malawi, Pakistan, Sri Lanka (Ceylon), Tanzania, Thailand, United States, and Zimbabwe (Rhodesia).

Ruby Spinel
A ruby spinel (or spinel ruby) is deep red, transparent spinel (not a ruby).

Rumanite
Rumanite is a type of opal that is from Romania.

Russian Gold Finish
A Russian gold finish is a matte, antique-look finish. Miriam Haskell jewelry often has a Russian gold (plated) finish.

Ruthenium
Ruthenium (abbreviated Ruth or Ru) is a precious metal that belongs to the platinum group of metals. In jewelry, ruthenium is added to platinum alloys; about 5 to 10 perent ruthenium can be added to platinum to harden and strengthen the alloy. Ruthenium’s atomic number is 44.

Rutilated Quartz
Rutilated quartz is a type of rock crystal which contains long, fine needles of rutile crystals (titanium dioxide). This beautiful stone is usually cut as a cabochon. It is also known as Venus’ Hair Stone, Cupid’s darts, and Fleches d’amour (arrows of love).

Safety Catch
A safety catch is a secondary closure (usually on a fine bracelet or necklace) that is used in case the primary clasp opens, preventing the loss of the jewelry. It is often a hinged, snapping loop that is permanently attached to one side of the clasp (often a box clasp), and, when the bracelet is closed, snaps onto the other side of the clasp.

Safety Chain
A safety chain is a secondary closure (usually on a fine bracelet or watch) that is used in case the primary clasp opens, preventing the loss of the bracelet. It is usually a chain that is permanently attached to one side of the bracelet, and attaches to the other side with a spring ring clasp (or other type of clasp). On the Miriam Haskell cuff bracelet above, the safety chain is located on the lower left of the picture.

Safety Clasp
A safety clasp is a secure type of closure on a piece of jewelry. The term safety catch is used for a variety of these closures. On pins and brooches, a safety clasp often refers to a long pin on a hinge that can be held or released with a secure clasp (often a rotating circle within a circle).

Salt
A colorless or white crystalline solid, composed of sodium chloride. It is found native in the earth, and is also produced by the evaporation and crystallization of sea water and other water impregnated with saline particles. Salt is used extensively in ground or granulated form as a food seasoning and preservative.

San Marco Chain
A unique kind of chain wherein each link is long and rounded, resembling a puffed grain of rice with a flat bottom. The links are arranged next to each other at a 45 degree angle and attached to each other on the bottom by sturdy flat pins set at an opposite angle.

Sand Casting
For hundreds of years sand casting was the most popular of all casting methods. It still plays an important role in the production of large metal forms, (typically Iron, but also Bronze, Brass, Aluminum). Tempered sand is packed onto wood or metal pattern halves, removed from the pattern, and metal is poured into resultant cavities. Molds are broken to remove castings.

Sandstone
Just as the name implies, sandstone is a sedimentary stone made of sand that has been fused with some cementing element like clay or quartz.

Sapphire
A precious gemstone (a type of corundum) that ranges in color from blue to pink to yellow to green to white to purple (mauve sapphire) to pink-orange (padparadscha sapphire). Six-sided asterisms sometimes occur in star sapphires (caused by inclusions of tiny, thin, parallel needles of rutile). Sapphires are related to rubies. Sapphires were once thought to protect the wearer from poisonous creatures. Sapphire has a hardness of 9 and a specific gravity of 3.9 – 4.1. Sapphires are often heat treated to improve their color.

Sapphire Quartz
Sapphire quartz (also called blue quartz) is another name for blue chalcedony.

Sard
A semi-precious stone related to carnelian. This brownish-red, opaque gemstone was once used extensively for seals and was carved using intaglio. Sard was named for Sardis, the ancient capital of Lydia. Sardius is mentioned in the Bible, and may refer to jasper.

Sardonyx
A semi-precious stone that is formed by two layers, a red-brown layer of sard and a gray, white, black or brown layer of onyx. Sardonyx is a type of quartz. Sardonyx is frequently carved to make intricate cameos and seals.

Satin Finish
A satin finish on a metal is between a matte finish and a brilliant one. This semi-glossy finish is done by making shallow parallel lines on the surface of the metal, reducing its reflectivity.

Saturation
A measure of the intensity of color inherent in a gemstone. Stones that are well saturated with color are more valuable.

Sautoir
A sautoir (also known as a rope) is a long necklace (longer than opera-length), often with an ornament (a tassel or pendant) at the end. Sautoirs were common during the Edwardian era.

Scalenohedral
A fancy shape gemstone made up of 12 facets, each shaped like a scalene triangle. Crystal points with triangular facets are said to be scalenohedral.

Scalloped
An ornamental border consisting of a series of curved projections.

Scarab
A scarab is a type of beetle. The ancient Egyptians used stones carved in the shape of scarabs extensively in their jewelry and other decorations. In the 1920s, after the tomb of King Tut was discovered in Egypt, Egyptian style jewelry became fashionable in the West, including scarab braclets and necklaces.

Scarabé
A type of iridescent finish applied to some dark glass beads. The scarabé finish mimics the look of iridescent scarab beetles.

Scatter Pins
Scatter pins are small pins that are worn together in small groups.

Scepter
A symbol of spiritual and worldly power used as a part of royal insignia. A scepter is really nothing more than a simple staff, but the ones used in ceremony are usually highly decorated with precious metals and gemstones. The topping of a scepter varied in different countries and in different periods. In the Middle Ages two forms were distinguished: a long staff (baculum), otherwise called rod, and a short one (sceptrum), although their meaning was identical. The long staff, topped with a globe, is a typical attribute of God in Carolingian painting. A scepter could be crowned with three leaves or a lily, a globe, a bird, etc.

Schiller
Schiller (from the German term for play of colors or glitter) is an iridescent or bronze-like luster occuring in some minerals (it is also referred to as labradorescence when it occurs in feldspars). This optical effect is caused by submicroscopic lamella (thin layers or flakes of inclusions) contained within the mineral. These layers of inclusions can produce a bronze-like luster, golden iridescence, red color-play, and/or a blue-green sheen that flashes when viewed from certain angles. This type of inclusion can be valuable (as in sunstone and labradorite). Layers of shiller can block reflected light, decreasing the stone’s brightness. Some types of feldspars (like labradorite, sunstone, spectrolite and peristerite) and other minerals (like hypersthene) exhibit schiller.

Schorl
Black Tourmaline.

Screw Back
A type of earring attachment for non-pierced ears where the earring is tightened against the earlobe by means of a screw with a flat padded end.

Scrimshaw
A type of folk art dating from at least the 17th century in which whale teeth, whale bones and walrus tusks are engraved or lightly carved with a picture or design. It was a way for sailors on long whaling voyages to pass time but has become very collectible.

Sea Glass
Sea glass (also called beach glass) is glass from old broken bottles, windows of wrecked ships, etc. that has been worn down and etched by the sea and sand over the years. This glass is smooth (with no sharp edges) and looks like beautifully sand-blasted glass with a soft patina. Pieces of this glass are collected on beaches and often made into jewelry items. Brown, deep green and clear are the most common colors of sea glass; after these come blue, amber and aqua. Rare colors include pink, red, purple, light yellow, and sea green.

Seal
Seals were once extensively used as a means of identification; they were only owned and used by relatively important people. Seals were usually mounted in rings or hung on a chain. Seals are carved in hard stones (like sard or jasper) using intaglio.

Seashell
Any of a number of shells of marine creatures such as mollusks or gastropods which can be used as jewelry. See cowrie shell, olivelia shell, abalone, ammolite, etc.

Sedimentary
Rock formed by layers of material that has accumulated and hardened over time.

Seed Bead
Mass produced tiny glass or plastic beads made by slicing tubes into tiny evenly spaced pieces. This makes them oblong in shape, rather than round, and flat on the ends. Seed beads can be strung together to make a necklace or bracelet, but are commonly used as spacers for larger beads. They can also be strung on a loom to make beaded bands and belts.

Seed Pearls
Seed pearls are tiny, round pearls that are less than 2 mm in diameter and weigh under 1/4 grain. Seed pearl jewelry was popular from the mid- to late-Victorian era, when the tiny pearls were strung on horsehair to form intricate designs and were also used as accents on other jewelry.

Seftonite
Seftonite is a translucent, moss green type of chalcedony. It is found in South Africa and North America.

Selenite
A soft, colorless-to-slightly-colored, transparent mineral. It is a crystalline variety of gypsum. Selenite has a hardness of 1-2 and a specific gravity of 2.3 to 2.4.

Selini
Selini was a costume jewelry company whose mark appears from the 1930s to the 1950s. Selini jewelry is usually intricate, well-designed, and often decorated with colored rhinestones and enamel. Very little is known about the company (If you have any information about the history of the company or the Selini mark, please email me).

Semi-Mount/Semi-Mounting
A finished piece of jewelry already embellished with gemstones and/or engraving that is simply waiting for the center stone. Pieces are sold this way to allow the buyer to add a center stone of their own choosing.

Semiprecious
Any gemstones valued for their beauty but which are not one of the four “precious stones”, (emerald, diamond, ruby or sapphire). Some examples of semiprecious stones are amethyst, aventurine, carnelian, garnet, opal, peridot, rose quartz, etc.

Semiprecious Gemstone
Any stone that is not classified as precious . Some examples are: turquoise, aquamarine, agate, jade, pearl, rose quartz, aventurine.

Serpentine
Serpentine is a green stone; there are two types of serpentine, bowenite and hydrated magnesium silicate. Bowenite is a jade-like stone (green to black) that is sometimes used in jewelry. The softer variety, hydrated magnesium silicate, is translucent serpentine has a hardness of 4 () – 5.5 (bowenite) and a specific gravity of 2.5 to 2.6. Serpentine is found in the British Isles and some other locations. Connemara marble (from Ireland) is a type of cloudy green serpentine.

Serpentine Chain
A series of small, flat, s-shaped links set very closely together and held in place by a second set of small, flat, s-shaped links set very closely together underneath them.

Setting
A setting is a method of securing a stone (or other ornament) in a piece of jewelry (or other object). There are many different types of settings, including the collet (a strip of metal surrounding the stone), the claw setting (in which prongs of metal hold the stone in place), Tiffany (a high,six-pronged setting), the cut-down setting (metal is worked around the edge of the gem, reinforced with metal ridges), pavé-set stones (stones set close together, showing no metal between them), millegrain (the stone is secured by small beads [grains] of metal), gipsy setting (with a recessed stone), and many other types (including combinations of the above-mentioned methods). Some settings are closed (there is metal behind the stone), while others are open (there is no metal behind the stone), letting light shine through the stone.

  1. G.
    S.G. (or s.g.) is an abbreviation for specific gravity, a comparison of a material’s weight with the weight of an equal volume of water.

Shank
The shank is the part of a ring that encircles the finger.

Shekel
A Hebrew unit equal to about a half ounce. A common estimate makes the shekel equal in weight to about 130 grains for gold, 224 grains for silver, and 450 grains for copper. A shekel is also a gold or silver coin equal in weight to one of these units, especially the chief silver coin of the ancient Hebrews. The approximate values of the coins are (gold) $5.00, (silver) 60 cents, and (copper half shekel), one and one half cents.

Shoulder
The part of a ring between the shank and the center of the setting.

Signet
A carved design, like an intaglio, which was usually worn on a ring. It was pressed into soft wax to authenticate a document. The design was usually a coat of arms, family crest, or some other type of insignia or monogram unique to the person using it.

Signet Ring
A signet ring is a ring that was used as a means of identification for relatively important people. The signet ring was engraved with a symbol (a coat of arms or initials) identifying a particular person. Some signet rings also had intaglio-carved seals. The earliest-known signet rings date from ancient Egypt, thousands of years ago.

Silicate
Any of a large group of minerals, forming over 90 percent of the earth’s crust, that consist of silicon, oxygen, and one or more metals, (and sometimes hydrogen).

Silicon
A nonmetallic element which is only found as a compound with other elements in nature. When artificially extracted, silicon appears as a dark brown amorphous powder, or as a dark crystalline substance with a metallic luster. This substance is used in combination with other materials in glass, semiconducting devices, concrete, brick, refractories, pottery, and silicones. Its oxide is silica, or common quartz, and in this form, or as silicates, it is the second most abundant element in the Earth’s crust, next to oxygen, making up 25.7% of it by weight.

Silky
The luster of a gemstone having a smooth, gleaming surface similar to silk or long silky fur. Tiger’s eye exhibits a silky luster.

Sillimanite
Sillimanite (aluminum silicate, Al2 SiO5) is a transparent to translucent mineral that ranges in color from white to gray to brownish to greenish. Sillimanite has the same chemical formula as both kyanite and andalusite (these three minerals are polymorphs); Sillimanite is the rarest of the three (all three are used in high-temperature ceramics, used in spark plugs). Sillimanite has a hardness of 7.5 and a specific gravity of 3.2. Sillimanite is the state mineral of Delaware (since March 24, 1977); SIllimanite is found near near Wilmington, Delaware. Sillimanite is found in Brazil, New England (USA), and Europe; it is found in areas of high-grade metamorphic rock.

Silver
Silver is a fine, silver-white metal often used in jewelry. Pure silver has a hardness of 2.5. Other metals are alloyed with silver (usually copper) for silver used in jewelry making. Silver tarnishes after exposure to air (a thin layer of silver-oxide forms on the surface). Silver often occurs near copper lodes.

Silver 800
Silver 800 is silver with a fineness of 800, that is, it contains 800 parts per thousand (or 80 percent) silver and 200 parts per thousand (or 20 percent) copper. Silver 800 is used for casting.

Singapore Chain
A style of chain wherein each link is composed of a series of flat, diamond-cut, interwoven concentric loops.

Single-Cut Diamonds
Genuine diamonds, commonly used in watchcases, that contain only 18 facets.

Silver Tone
Jewelry finished with a silver color with very little appreciable measurement of weight in silver.

Silvery Finish
Jewelry that has the look of silver but no actual silver content.

Simulated Stones
Any natural or synthetic substance which is meant to resemble a gemstone. cubic zirconia, for example, is a simulated diamond.

Simulated Tortoise
A synthetic material resembling the mottled brown and yellow color found on tortoise shells.

Slab
A slab is a broad, flat, relatively thin piece of stone cut from a larger chunk of stone. Lapidaries use slabs when cutting cabochons or material for jewelry inlay work.

Slate
A smooth, solid gray fine-grained rock that can be split into thin layers.

Sleeper
A sleeper is a small hoop-earring made of gold that is used to keep the hole in a pierced ear open.

Sliced
A bracelet that is the same thickness all the way around and does not taper at the edges; as though it were simply sliced off the end of a cylinder.

Slide
An ornament with a tube on the back. A cord or necklace can then be threaded through the tube allowing the ornament to slide along the length of the cord or necklace. See Bolo.

Slide Bracelet
(also called slide charm bracelet) A slide bracelet is a type of modern-day charm bracelet made from stringing Victorian era watch fob charms together on a double chain – the charms can slide along the chains. When pocket watches (used by men) and nceklace watches (used by women) went out of style after wrist watches were invented, the charms on the watch chain were removed and then strung together to make bracelets. Modern imitations are made using modern-manufactured charms.

Smoky Quartz
Smoky quartz is a type of brownish quartz that has a smoky look.

Smoky Topaz
see Smoky Quartz.

Snake Chain
A snake chain (also called a Brazilian chain) is a metal chain made up of a series of small, linked cups.

Snap Bar Closure
The hinged bar on the back of a lever back or omega back earring.

Snowflake Obsidian
Snowflake Obsidian (also called flowering obsidian) is a volcanic glass that is usually dark (black or brownish) with white “snowflakes”. This glassy, lustrous mineral is found in lava flows, and obsidian stones can be massive. Obsidian is formed when viscous lava (from volcanos) cools rapidly. Most obsidian is 70 percent silica. Obsidian has a hardness of 5 and a specific gravity of 2.35.

Soapstone
Soapstone (also called steatite) is a soft, easily-carved, fine-grained metamorphic rock that can be green, brown, or gray. This stone has a greasy, soapy feel to it, hence its name. Soapstone is found worldwide. It is carved into figurines, beads, seals, bowls, pipes, cookware, and other items – it has been used since ancient times. Chemically, soapstone is composed mostly of talc, hydrated magnesium silicate (Mg3Si4 O10(OH)2) plus other minerals. Soapstone has a hardness of 1-1.5 (extremely soft – it can be scratched with a fingernail) and a specific gravity of 2.2-2.8.

Soda
Any of various forms of sodium carbonate used in making soap, powders, glass, and paper.

Sodalite
Sodalite is a dark blue mineral with streaks of white, gray, pink, or green. It is used for carvings and jewelry. Sodalite is one of the mineral components of lapis lazuli. . Sodalite is sodium aluminum silicate chloride; its formula is Na4Al3(SiO4)3Cl. Sodalite has a hardness of 5.5 to 6 and a specific gravity of 2.1 – 2.3. Sodalite is found in Brazil, Canada, India, Italy, Namibia, United States, and Russia.

Sodium
A common soft, waxy, light, extremely malleable silver-white unstable metallic element of the alkali group. It is always found as a compound with other elements in nature, such as common salt, albite, etc. Sodium burns with a yellow flame, and is so readily oxidized that it combines violently with water and to be preserved must be kept under petroleum or some similar liquid.

Solder
Solder is a metal alloy (a mixture of metals) thatis used to join other metals. Solders melt at a lower temperature than the metals to be joined.

Soldering
A technique used in making and repairing jewelry whereby two pieces of metal are joined by applying a molten metal which has a lower melting point than the two metals being joined.

Solitaire
A solitaire is a ring set with a single stone, usually a diamond.

SPARKLE
A measure of the light reflected out by a diamond or stone as it is viewed from different angles.

Specific Gravity
The specific gravity (abbreviated s.g.) of a material is a comparison of its weight with the weight of an equal volume of water. Specific gravity measures the density of a material.

Spectrolite
Spectrolite is another name for Finnish Labradorite (a variety of plagioclase feldspar). It is a fairly abundant grayish mineral that has brilliant iridescent flashes of color (usually green, blue, orange, or red) after it is polished. The crystals are transparent to translucent. Spectrolite is usually cut with a flat surface in order to highlight the brilliant flashes of color. Spectrolite has a hardness of 6 to 6.5 and a specific gravity of 2.70.

Spectroscope
A spectroscope is an instrument that is used to identify gemstones. It works by determining the light waves that a stone absorbs; different stones absorb different wavelengths of light.

Spessartine Garnet
Spessartine garnet (also called Spessartite garnet) is a type of a garnet that is orange (it varies from reddish orange to brownish orange to yellowish orange). The chemical composition is Manganese Aluminum Silicate. Crystals vary from transparent to translucent. This relatively rare gem is found in Sri Lanka, Australia, Madagascar, Brazil, Sweden, Myanmar, and the U.S. Spessartine garnet has a hardness of 7.0 – 7.5, a specific gravity of 4.19 (relatively heavy), and a refractive index of 1.8.

Spessartite
A red to brownish-red garnet composed of alumina manganese.

Sphene
Sphene (sometimes called titanite) is a mineral that comes in green, yellow, white, brown or black wedge-shaped crystals (sphene means wedge in Greek). Sphene is used only rarely as a gem (due to its relative softness). It’s chemical formula is CaTiSiO5, Calcium Titanium Silicate. Sphene has a hardness of 5-5.5, a specific gravity of 3.3 – 3.6, and a white streak.

Spinel
Spinel is a very hard semi-precious stone composed of octahedral crystals. Spinel ranges in color from red to black to yellow, frequently resembling rubies. Iron and chrome are components of spinel, giving it its color. Spinel belongs to the feldspar species and is found in in Burma, Sri Lanka and Thailand. Some varieties include: Balas ruby (red spinel), Almandine spinel (purple-red), Rubicelle (orange), Sapphire spinel (blue), Ghanospinel (blue), Chlorspinel (green). Spinel is also laboratory synthesized. Spinel has a hardness of 8, a specific gravity of 3.58-4.06, and a refractive index of 1.72.

Split Ring
A tightly-coiled ring used as an jewelry finding; it can attach charms to a charm bracelet or a clasp to a necklace or bracelet (it is like a miniature version of a keychain).

Spray Brooch
A type of brooch, usually worn at the shoulder, which is characterized by floral themes featuring long stemmed jeweled flowers and long leaves.

Spring Ring
A spring ring (also known as a bolt ring) is a hollow circular metal fastening ring with a spring opening. A tiny spring keeps the arm of this clasp closed. It is used to attach two other rings or links of a necklace or bracelet. The spring ring was invented early in the 1900’s. Jewelry made prior to 1900 or so will not have a spring ring clasp.

Spring Ring Clasp
A very common kind of clasp used for joining two ends of a necklace. The clasp itself consists of a hollow metal tube in a circle shape with a gap in the side. The hollow tube contains a small wire held in place by a spring inside the tube behind the wire. The wire can be pulled back by means of a small knob which slides along the outer edge of the circular tube. Releasing the knob allows the spring to push the wire forward closing the gap. The other end of the necklace terminates in a small ring. By using the knob on the spring ring to open the gap in the hollow circular tube, one can then place the small ring through the gap and close the wire through the ring securing it in place and closing the necklace.

Square Cut
A style of gem cutting resembling the emerald cut.

Square Setting
A square shaped setting with a prong at each corner.

Squarillion Cut (SQUARE CUT)
A Squarillion cut is a square-cut stone. This fancy cut is relatively new and is also known as a Princess or Quadrillion cut.

Squash Blossom Necklace
A traditional piece of Navajo jewelry based on an old and favored Spanish-Mexican ornament which was actually not a squash, but a stylized version of the pomegranate. A shape that the Spanish Conquistadores used as buttons on their trousers. The squash blossom necklace is composed of beads resembling squash blossoms placed at regular intervals with a naja, (crescent shaped pendant), at the center.

SS
SS is an abbreviation for sterling silver.

Stabilized Stones
Stabilized stones have been impregnated with plastic to improve its durability, stabilize cracks, and improve the stone’s appearance (a dye is sometimes added to the plastic – this is called a color shot or color stabilized). Liquid plastic resins are injected into soft, porous stone at high pressures – the plastic fills the pores in the stone. Turquoise is often stabilized.

Stabilized Turquoise
Turquoise is very porous by nature which allows it to absorb any pollutants that it comes in contact with, including oils from the skin. Stabilized turquoise has been treated by various methods to reduce the porosity, thus making less changeable over time.

Stack Rings
Two or more rings that are designed to be stacked on the same finger at the same time.

Stainless Steel
An extremely durable alloy of steel and chromium which can be polished to resemble a precious metal and is virtually immune to rust, discoloration and corrosion.

STAMPING
Using a punch or die to cut or emboss a sheet of metal with a mark.

STAR
The Star Company of Houston, Texas, manufactured costume jewelry beginning before 1930. Pieces often include thermoset plastic “jewels.”

STAR OF AFRICA
The Star of Africa (also called the Cullinan diamond) is the largest diamond yet found, weighing 3,106 carats (roughly 1.3 pounds) in its rough form. It was mined at the Premier Mine in South Africa in 1905. This enormous gem was named for the chairman of the company that owned the mine. It was given to King Edward VII of England for his birthday in 1907. The diamond was cut (by Joseph J. Asscher of Amsterdam) into many stones, including the Cullinan I (530 carats, pendelique-brilliant shaped, the largest cut diamond in the world), the Cullinan II (317 carats, cushion shaped), Cullinan III (94 carats, pendelique shaped), Cullinan IV (63 carats, square-brilliant shaped), and many other smaller stones.

STAR GARNET
A “star garnet” is almandine that exhibits an asterism. Almandine is a type of garnet that ranges in color from deep red to reddish-brown.

STAR OF INDIA
The Star of India is a huge, blue, star sapphire weighing 563.35 carats. It is cut as a cabochon. This gemstone was found in Sri Lanka (date unknown). A British Army officer brought it to London, where it was cut by Albert Ramsay around 1905. It is now at American Museum of Natural History.

STAR OF THE SOUTH
The Star of the South is a the largest diamond found in South America. This Brazilian stone weighs 254.5 carats.

STAR RUBY
A “star ruby” is a ruby that exhibits an asterism, a six-pointed star of light (when cut as a cabochon). The world’s biggest star ruby is the Rajaratna, which weighs 2,475 carats. The world’s biggest double-star ruby (with a 12-pointed star) is the Neelanjali, weighing 1,370 carats. Most star rubies today are synthetic.

STAR SAPPHIRE
A star sapphire is a sapphire that exhibits an asterism in the form of a colorless, six-rayed star that reflects light. Star sapphires are cabochon cut. Laboratory-produced star sapphires (“Linde stars”) were developed in 1947 by the Linde company; most star sapphires today are synthetic.

STAR SETTING
A star setting is one in which a gem is set within an engraved star; the gem is secured by a small grain of metal soldered tp the base of each ray of the star. This type of setting was popular in the 1890s.

STATER
A silver coin from ancient Greece.

STEATITE
Steatite (also called soapstone) is a soft, easily-carved, fine-grained metamorphic rock that can be green, brown, or gray. This stone has a greasy, soapy feel to it, hence its name. Soapstone is found worldwide. It is carved into figurines, beads, seals, bowls, pipes, cookware, and other items – it has been used since ancient times. Chemically, soapstone is composed mostly of talc, hydrated magnesium silicate (Mg3Si4 O10(OH)2) plus other minerals. Soapstone has a hardness of 1-1.5 (extremely soft – it can be scratched with a fingernail) and a specific gravity of 2.2-2.8.

STEP CUT
The step cut is generally used for colored stones. This cut is rectangular to square and has many facets parallel to the edges of the stone.

STERLING
Sterling is silver with a fineness of 925, that is, sterling is 925 parts per thousand (or 92.5%) silver and 75 parts per thousand (or 7.5%) copper (the copper increases the silver’s hardness). Sterling is quite malleable.The pin pictured above is a rhinestone-studded sterling bow made by Trifari.

STERLING SILVER
Sterling is silver with a fineness of 925 parts per thousand or 92.5% silver and 75 parts per thousand or 7.5% copper. Copper is added to the alloy to increase the silver’s hardness.

STICK PIN
A pin with an ornament on the top worn vertically on a scarf, tie, or lapel. Also called a “tie pin” or “lapel pin”

STIPPLED FINISH
A texture formed by a series of pricks made with a steel punch.

STRASS
Strass is highly reflective glass that is made to imitate gemstones. The original rhinestones were quartz stones obtained from the Rhine river. These stones were cut to resemble gemstones.

STREAK
The streak of a mineral is its color when it is in powdered form. You can determine the streak of a mineral easily by rubbing a rough mineral (not cut stones!) along the surface of a hard, unglazed porcelain sheet (this is called a streak plate – you can use the back of a white porcelain bathroom tile). Even though the color of a mineral may vary, the streak color is constant. Note: the streak plate has a hardness of about 6.6, so it can only test mineral that less hard than that (since they must leave a streak on the porcelain). For example, the streak of chalcopyrite, graphite, magnetite, and pyrite is black, the streak of galena is gray, the streak of cinnabar, the streak of azurite and lapis is blue, the streak of malachite is green, the streak of turquoise is white with a green tint, the streak of olivine, amethyst, and tourmaline is white, and the streak of hematite is red-brown.

STRIATIONS
Striations are grooves, lines and scratches found naturally in some minerals.

STUD
A simple style of earring for pierced ears that has a single stone (such as a pearl) or metal ball on a straight post with no dangling parts. (See also Button earring).

SUGAR BEADS
Sugar beads are beads that look as though they were rolled in granulated sugar; the fine grains on the surface of the beads are in fact tiny grains of glass (or plastic). Delicate glass sugar beads were made in Gablonz and Japan early in the 20th century.

SUGILITE
Sugilite is a medium to dark purple semi-precious gemstone (it can also range from pink to brown to black). It is usually opaque with a waxy luster (but can be translucent) and often has brown, pink and white inclusions, looking like a purple version of turquoise. It is usually polished and not faceted. Sugilite has a hardness of 5.5-6.5 and a specific gravity of 2.75 – 2.80. This stone is not enhanced – massive stones are often found. Sugilite is Potassium Sodium Lithium Iron Manganese Aluminum Silicate; its formula is KNa2Li3(Fe, Mn, Al)2Si12O30. This stone was named for Ken-ichi Sugi, the Japanese geologist who discovered it in 1944. It is found in Iwagi Island, Shikoku, Japan and Mont Saint-Hilaire, Quebec, Canada, but the largest deposits are in northern South Africa.

SULFATE
A salt containing sulfur dioxide.

SULFUR
An abundant, pale yellow, nonmetallic element used in black gunpowder, rubber vulcanization, the manufacture of insecticides and pharmaceuticals, and in the preparation of sulfur compounds such as hydrogen sulfide and sulfuric acid.

SULPHUR
A variant spelling of sulfur.

SUNSTONE
Sunstone is also called aventurine feldspar (a variety of oligoclase). This gemstone varies from golden to orange to red-brown, and can be transparent or translucent. Sunstone is metallic-looking due to sparkling red, orange or green crystalline inclusions (these are hematite or goethite crystals). Sunstone is found in Canada, the USA (in Oregon), India, Norway, and Russia. This brittle stone has a hardness of 6 and a specific gravity of 2.63 – 2.67. Sunstone is not enhanced.

SWISS LAPIS
Swiss lapis is not lapis lazuli at all. It is jasper dyed to resemble lapis lazuli and is misleadingly called “Swiss lapis.”

SYMMETALIC
Symmetallic is a mark used by the W. E. Richards Company of North Attleboro, Massachusetts, USA. This company made very good quality silver, gold-plated silver, and low-carat gold jewelry. Pieces often havae cultured pearls, moonstones, and other semi-precious stones. The mark SYMMETALIC was first used in December, 1936.

Symmerty
How similar one side of an object is to the other side. The lengths and angles on each side of a faceted gemstone are closely compared. The more uniform the cut, the higher the value of the stone.

Synthetic
Gemstones produced in a laboratory rather than found in nature. Synthetic gemstones are not “fake”, since they have exactly the same chemical characteristics as the natural stone, but they are usually flawless and much cheaper than the real thing. The most common synthetic gems are emeralds, rubies, sapphires and opals.

Synthetic rubies
Synthetic rubies were first made by the French chemist Auguste Verneuil, who invented the flame-fusion process for producing inexpensive rubies in 1886. It was a ruby, but it didn’t look much like one. In 1918, J. Czochralski invented the pulling method for growing inexpensive rubies. Carroll Chatham synthetic rubies (more expensive to produce, but natural-looking) were introduced in 1959. Kashan synthetic rubies were made beginning in 1979.

Synthetic Stones
Synthetic stones are made in laboratories; these stones generally lack imperfections. It is very difficult to distinguish a synthetic stone from a natural stone.

Synthetic Turquoise
A man made chemical identical with that of the natural stone.

Tabasheer Opal
Tabasheer (also spelled tabashir) or pearl opal is an organic stone that forms in damaged joints (nodes) of bamboo plants. This hydrated form of silica appears as a rounded mass of opal, and looks like seed pearls.

Table
The table is the large, flat area at the top of a cut gemstone.

Table Percentage
The size of the table of a cut gemstone in proportion to the girdle obtained by dividing the table width by the girdle width

Tahitian Pearl
Tahitian pearls (also called black pearls) are dark-colored pearls. They are produced by the large, black-lipped pearl oyster Pinctada margaritifera (also called the Tahitian black pearl oyster), a mollusk found in the tropical Indo-Pacific Ocean. Black pearls come in many colors, including many body shades and overtone tints including gray (light gray to almost black), peacock green (especially valuable), aubergine (eggplant), and deep brown. The color of the dark nacre is determined by the minerals in the oyster’s diet (plankton) and in its environment. Many “black pearls” are dyed or irridiated to enhance or change their color; it is difficult to tell a natural pearl from a treated pearl. Tahitian pearls are graded on six factors: 1.Shape (round is most valued), 2.Size (the larger the better), 3.Surface Quality (clean is superior to blemished), 4.Luster (the more high-gloss luster the better), 5.Nacre Thickness (thicker is better and longer lasting), and 6.Color (overtones atop the body color add value to the pearl; the most sought-after color is peacock green and darker colors are more valuable – overtone colors include blue, pink, gold, silver, aubergine, and peacock green).

Talisman
A stone, ring, charm or other object marked or engraved with signs or characters that is believed to possess magical powers to protect the wearer from harm. Also, see amulet.

Tantalum
A rare, very hard, heavy, gray metallic element that is exceptionally resistant to corrosion and chemical attack below 150°C. It is used to make light-bulb filaments, electrolytic capacitors, lightning arresters, nuclear reactor parts, and some surgical instruments.

Tanvorite
Tanvorite is a trademarked name for a manmade gemstone. This synthetic stone is a deep blue-purple stone that resembles tanzanite.

Tanzanite
Tanzanite (strontium-rich Calcium-aluminum silicate) is a valuable, transparent, blue-violet type of zoisite resembling sapphire. Tanzanite has a hardness of 6 and a specific gravity of 3.35. It is often heat-treated in order to produce a deeper blue-violet color. This mineral was discovered in 1967 by Manuel d’Souza (an Indian tailor) southwest of Mt. Kilimanjaro in Tanzania, Africa. Tanzanite is one of December’s birthstones.

Tapered Baguette
A small gemstone cut in a trapezoid shape with one end narrower than the opposite end.

Tarnish
A dulled luster or finish caused by a thin deposit of a dirt which discolors the surface of metal and is easily removed. Also a reaction between metals and other chemicals which discolors the surface, particularly silver which reacts with sulfur. The silver sulfide can be removed with a proprietary cleaning product and gentle abrasion.

Tassel
A bundle of threads bound at one end and loosely hung as an ornament.

Tavorite
Tavorite is a green to greenish-yellow to yellow gemstone. This vitreous (glassy) stone, a Lithium Iron Phosphate, has a hardness of 5 and a density of 3.28 (tavorite belongs to the Amblygonite Group, phosphates that have a triclinic crystalline structure). Tavorite was named in 1955 by the mineralogists M. L. Lindberg & W. T. Pecoria for the Brazilian mineralogist Elysairio Tavora (1911- ). The chemical formula for tavorite is LiFe3+(PO4)(OH). The streak is light green. Tavorite is found in Brazil, Germany, Portugal, and USA (South Dakota and New Hampshire).

Temper
To temper is to strengthen or harden metal (or glass) by heating it or by heating then cooling it. Harder tempers are stronger, more spring-like, and brittler (when they are bent, they may break). Softer tempers are weaker but bend easily.

Template
A cut out pattern used to trace a design; like a stencil.

Tennis Bracelet
A tennis bracelet is a simple, flexible, in-line diamond bracelet. The name tennis bracelet was first used when the great tennis player Chris Evert dropped a diamond bracelet during a tennis match in the summer of 1987 (at the US Open Tennis Tournament). She had to stop the match until she found her bracelet. Since then, that style of bracelet has been called a tennis bracelet.

Tennis-Style
A style similar to a tennis bracelet with individually set stones linked together in a chain, but not necessarily of uniform size or color.

Thermoluminescent
Thermoluminescent minerals emit bright light when heated. For example, chlorophane is a varity of fluorite that emits bright green light when heated.

Thermoset Plastic
Thermoset plastic (also known as thermoplastic) is a hard, non-rigid synthetic substance that cannot be melted by reheating. Thermoset plastic is formed under high heat or pressure by a process known as polycondensation. Bakelite is a thermoset plastic. The bangle above is “butterscotch” bakelite.

Tiara.
A lady’s hair ornament worn on formal occasions that curves with the natural line of the head.

Tie Bar
A tie bar is a piece of men’s jewelry used to secure a necktie. A tie bar usually has a decorative, bar-shaped front, and a clip on the back that grasps the two parts of the tie.

Tie Tack
A tie tack is a piece of men’s jewelry used to secure a necktie. A tie tack has a decorative front, and a pin on the back that goes through both layers of the tie. Attached to the reverse of the pin is a chain with a bar that is meant to go throught a buttonhole to secure the tie loosely to the shirt.

Tiffany Setting
The Tiffany setting is a ring with a high, six-pronged solitaire diamond on a simple circular band. This design was introduced by Tiffany & Co. in 1886.

Tiger’s Eye
Tiger’s eye is a yellowish-brown to reddish-brown gemstone that has a silky luster. This gemstone has bands of yellow and brown; when viewed from the opposite direction, the colors are reversed. Tiger’s eye is usually highly polished and set as a cabochon (or cut as a bead) to display the stone’s chatoyancy (light reflected in thin bands within the stone). Tiger’s eye is a type of chatoyant quartz with fibrous inclusions (especially crocidolite). This stone is sometimes heat-treated. Tiger’s eye has a hardness of 7.0. Most tiger’s eye is mined in South Africa, but it is also found in Australia, Brazil, Burma (Myanmar), India, Namibia, Sri Lanka (Ceylon), and the USA. Green-grey varieties of this stones are called cat’s-eye quartz. Blue-grey to bluish varieties are called hawk’s-eye. Deep brown varieties of this stone are called bull’s-eye or ox-eye.

Toggle Clasp
A toggle clasp (also called a bar and ring clasp) is a jewelry fastener in which a bar can be inserted into a ring to fasten a piece of jewelry. It is used to attach the two ends of a necklace or bracelet.

Topaz
Topaz (aluminum silicate fluoride hydroxide) is a very hard gemstone that ranges in color from brown, to yellow to blue to pink. Pink topaz is usually created by irradiating common yellow topaz. Other colors are often created by heat-treating and/or irradiating topaz. Imperial topaz is golden orange-yellow topaz; it is the most valuable topaz Topaz has a hardness of 8 and a specific gravity of 3.5-3.6. Topaz may have been named for the legendary Topasos Island in the Red Sea.

Torque
A torque (also spelled torc) is a necklace that consists of a narrow, twisted band made of metal. This type of ornament was worn by the ancient Celts, Britons, and Gauls.

Torsade
A torsade is a necklace made of many strands that are twisted together.

Tortoise Shell
Tortoise shell is the shell of a tortoise. It was used in the 1800’s for jewelry, hair combs, and other ornaments but is banned today. Tortoise shell inlaid with precious metals is called pique. Tortoise shell will burn easily, and smells like burning hair. It is easily imitated by plastic, but its smell when burnt is very different. Tortoise shell has a hardness of 2.5 and a specific gravity of 1.29.

Tourmaline
Tourmaline is a dichroic gemstone that comes in many, many different colors; it also appears to have different colors depending on the angle at which it is seen. Tourmaline has the greatest color range of any gemstone – the lighter colors are more valuable than the darker colors. It ranges in color from pink to green to red (rubellite) to purple to blue-green (indicolite) to colorless (achroite) to black. Watermelon tourmaline is both pink and green. Tourmaline occurs as an elongate three-sided prism and is mined in Brazil, The Ural mountains in Russia, Namibia, Sri Lanka, and California. Tourmaline was only discovered in the 1700’s. Tourmaline has a hardness of 7-7.5 and a specific gravity of 3.02-3.25. It is doubly-refractive.

Tourmalinated Quartz
Tourmalinated quartz is a variety of transparent quartz that has needle-like inclusions of black to dark green tourmaline crystals. This beautiful stone is found worldwide. Tourmalinated quartz has a hardness of 7.0. This stone is not enhanced.

Translucent
Translucent materials allow light to pass through them, but the light is diffused (scattered). Some translucent stones include moonstones, opals, and carnelian. Lucite and other plastics can also be translucent.

Transparent
Transparent materials allow light to pass through them without diffusing (scattering) the light. Some translucent stones include diamond, zircon, emerald, rock crystal, and ruby. Plastics like lucite can also be transparent. In the confetti lucite bangle above, the glitter within the lucite is visible.

Transvaal Jade
Transvaal jade is not jade; it is a green to gray massive variety of grossular garnet, calcium-aluminum silicate. It is found about 40 miles west of Pretoria, South Africa. Transvaal jade can be distinguished from jadeite or nephrite by its high refractive index. Grossular garnet has a refractive index of 1.72 to 1.73, a hardness of 6-7.5 and a specific gravity of 3.5 – 3.67.

Trapiche Emeralds
Trapiche emeralds are rare, valuable emeralds that have a black, six-rayed star within them, caused by black carbon impurities (the star is not an asterism). These stones are usually cabochon cut to display the beautiful spoke-like star. These stones are only mined in Colombia, South America. Trapiche emeralds are sometimes called star emeralds (but the term star emerald can also refer to emeralds with an asterism). Trapiche is a Spanish word for the spoked wheel that is used to grind sugar cane.

Trap Rock
Trap rock is a type of igneous rock. This solidified lava often contains pockets of crystals.

Treated Turquoise
A process by which the pore spaces of the stone are filled with a transparent substance such as mineral oil, paraffin, or plastic to improve the color, and make it more desirable.

Trembler
A trembler is a piece of jewelry that has a part (or parts) set on a spring; the spring-set parts move as the wearer of the jewelry moves.

Trillion Cut
The trillion cut is a triangular cut based upon a brilliant style cut (and not a stepped facet). The corners of the triangle are truncated (cut short) and there are a variety of facets, giving this cut a sparkling billiance.

Triplet
A triplet is a manufactured stone that is made by sandwiching three thin layers of stones together. For example, an opal triplet had a top, protective layer of clear quartz, a thin middle layer of opal, and a base layer of dark, color-enhancing matrix (usually black onyx or ironstone).

Troy Weight
Precious metals (like gold, platinum, and silver) are measured in troy weight, which has units of pennyweights, ounces, and pounds. Troy ounces and pounds are different from everyday US measures.

Tsavorite
Tsavorite is a rare, deep green variety of grossular garnet, a type of garnet, calcium-aluminum silicate. The emerald green color comes from vanadium and chromium. Tsavorite is similar to emerald, but is rarer and more durable; it also has a higher refractive index, 1.74. Tsavorite stones over two carats are considered large and are very rare. Tsavorite has a hardness of 7.5 and a specific gravity of 3.6. Tsavorite is found in east Africa; it was named by Harry B. Platt of Tiffany & Co. for the Tsavo National Park in Kenya, where this gemstone was originally found in 1967. Tsavorite is not enhanced.

Tumbled
Tumbled stones were finished in a tumbler, a mechanical device that smooths and rounds the surfaces of stones. Tumbled stones look very much like stones that have been in a fast-flowing river or stream for a long time.

Tumbler
A tumbler is a rotating cylinder (powered by a motor) that smooths and rounds the surfaces of stones, increasing their luster. As the stones tumble around the cylinder, they bump against each other and smooth each other’s surfaces.

Turquoise
A non-translucent, porous semi-precious stone (it is a hydrated phosphate of copper and aluminum) that is usually cut as a cabochon. Turquoise was believed to have been first found in Turkey, hence its name (Turquie is the French word for Turkey). The oldest turquoise mines are located in Alimersai Mountain in Persia (Iran) and in the Sinai Peninsula in Egypt. Turquoise is found in desert regions worldwide. The finest turquoise is Persian (Iranian) turquoise; it is robin’s egg blue and has no matrix (streaks of the mother stone from which they were found). North American turquoise is greener and has a matrix streaks. Over the years, oil from your skin is absorbed by the stone and it will change color slightly. Turquoise has a hardness of 6 and a specific gravity of 2.60-2.85. Turquoise is the national gemstone of Iran. Turquoise is one of December’s birthstones

Twinning
Twinning is a common error in crystalization in which two crystals grow out of one another or next to one another, and their crystal lattice is oriented differently from one another (some twins are like a mirror image of each other). If the crystals have grown into one another, they are called penetrant twins (forming a cross-shape like Staurolite, a star-shape like Muscovite, and other unusual shapes). If the crystals are mirror images that grow next to one another, they are called contact twins (they are often likened to Siamese twins). Twinning can drastically change the outward symmetry of the mineral specimen, by either increasing or decreasing the symmetry (like with spinel). For example, twinning can make an orthorhombic crystal appear to be hexagonal (as in Aragonite).

Ultrasonic cleaner
A machine that cleans jewelry by using a fluid that is vibrated at 20,000 cycles per second. When the vibration speed rises above the ultrasonic frequency level, bubbles explode and generate strong power, cleaning the surfaces and cavities of hard-to-clean objects. Ultrasonic cleaning does not scratch the surface or harm objects like many chemical or abrasive cleansers.

Unakite
Unakite is an opaque mineral that is green with patches of red and pink. Unakite is a variety of granite that contains green epidote and pink feldspar (but lacks mica). It has a hardness of 6 to 7 and a specific gravity of 2.86 – 3.2. Unakite was named for the Unaka Mountains Mountains in Tennessee, USA. Unakite is found in the USA and Africa.

Uvarovite
Uvarovite is a rare emerald-green Garnet. It is not used a faceted gem because the crystals are too tiny. However, as drusy has come into popular use in jewelry, the stone is cut en cabochon and used in pendants, earrings and pins.

Vabanite
Vabanite is a type of brown-red jasper with yellow flecks that is found in California, USA.

Valadium
A fine stainless steel that resembles white gold.

Variscite
Variscite is a relatively rare phosphate mineral which is sometimes confused with chrysocolla or the greener forms of turquoise. Colors are light bluish green, medium and dark greens. It often contains patches of white, gray or brown matrix, has a waxy luster and takes a fine polish. Mohs scale of hardness 3.5 – 5.

Venus’ hair stone
Venus’ hair stone is another name for rutilated quartz.

Vermeil
(Vehr-MAY) A substantial amount of real gold which has been chemically bonded to sterling silver. The finish looks so much like solid gold that, except for the price, it is difficult to tell the difference.

Victorian
Belonging to the period of the reign of Queen Victoria of England (1837-1901). Jewelry of the Victorian period was highly ornamental.

Vienna turquoise
Vienna turquoise is fake turquoise made by compressing a precipitate of aluminum phosphate (colored with copper oleate).

Vitreous
The tem used to describe a gem that has a glassy luster.

Vulcanite
A hard, moldable dark brown or black plastic used for memorial pieces in the mid-Victorian period.

Watermelon Tourmaline
Watermelon tourmaline is a tourmaline gemstone that is multicolored, going from pink to green. The Schreiner pin above is made of paste (glass) watermelon tourmaline.

Water sapphire
“Water sapphire” is not a true sapphire, but is iolite, a more common, softer, and much less expensive mineral. It is a transparent, violet-blue, light blue, or yellow-gray mineral. Iolite is pleochroic; a single stone will show many colors (in the case of Iolite, violet-blue, light blue, and yellow-gray). Iolite has a hardness of 7 – 7.5. Iolite is found in Sri Lanka, India, Madagascar and Burma.

Wax Pearl
Wax pearls are hollow glass beads that are filled with wax and resemble pearls.

Waxy
This is a term used to describe the luster of gem. Some gems that exhibit a waxy luster are: carnelian, chalcedony, turquoise.

Wedding cake beads
Wedding cake beads are lampworked glass beads that are decorated with intricate, colorful glass overlays, often of roses and decorative swirls and dots. This type of bead was originally made in Murano, Italy.

Weld
Welding is a process that joins two pieces of metal using very high heat. Rolled gold is formed in this fashion.

White Gold
An alloy of gold made with nickel. Sometimes the jeweler also mixes palladium or zinc in the alloy. White gold has a brighter and whiter color than silver due to the nickel content.

White Metal
Any combination of alloys of nonprecious metals such as lead and tin. Also called “Pot Metal”.

White Onyx
A form of agate from the chalcedony family which is semi-translucent with white to yellowish-white banding.

White Quartz
A translucent white mineral consisting of silicon dioxide in crystal form. White Quartz is basically clear quartz with a high degree of cloudiness. It is usually uniform in terms of the color, but has areas of more or less opacity.

Wholesale
Of, relating to, or engaged in the sale of goods in large bulk or quantity for resale by a retailer or jobber rather than directly to consumers.

Width
The horizontal measurement across the widest area of an item of jewelry.

Xaga
Xaga is a type of obsidian found in California, USA.

Xalostocite
Xalostocite is a pink grossular garnet that is found in a matrix of white marble. Xalostocite is found in Xalostoc, Mexico.

Xenolith
A xenolith (also called an inclusion) is a fragment of foreign rock that is embedded inside an igneous rock.

Xyloid Jasper
This is petrified wood that consists mostly of jasper. The original chemicals are replaced with minerals leaving a replica of the original wood in stone. See Palmwood.

Y necklace
Usually 16 to 18 inches in length, this style of necklace gets its name from its shape which features a dangle forming a Y-shape around the neck.

YAG
YAG is an actonym for yttrium aluminum garnet, a man-made imitation diamond. This imitation stone lacks the fire of a natural diamond.

Yellow Gold
Yellow gold is gold that has been alloyed with a mix of 50% copper and 50% silver.

Yowah Nut
A form of Boulder Opal from Yowah (Queensland), Australia. It occurs most often as nut-sized ironstone nodule containing pockets and veins of vivid precious opal.

Yttrium
A silvery metallic element of the boron-aluminum group, found in gadolinite and other rare minerals, and extracted as a dark gray powder. Not a rare earth but occurring in nearly all rare-earth minerals, used in various metallurgical applications, notably to increase the strength of magnesium and aluminum alloys.

Zamak
Zamak is a zinc alloy containing some aluminum (3.9-4.5%) and copper (0.02-0.05%).

Zinc
An abundant, lustrous, bluish-white, metallic element of the magnesium-cadmium group. Zinc is brittle at room temperature but malleable when heated. It is used to form a wide variety of alloys including Brass, Britannia, Bronze, various solders, and Nickel Silver. Because zinc is not easily oxidized in moist air it is used for sheeting, coating galvanized iron (and other metals), for electric fuses, anodes, meter cases, in roofing, gutters, and is also largely consumed in electric batteries.

Zircon
Zircons are very common minerals which occur naturally in clear, yellow, brown, orange and reddish-brown colors. Zircon is frequently heat treated to enhance or alter their color. Mohs scale: 6.5-7.5. Many people confuse the natural gem zircon with cubic zirconia which is a man-made, synthetic used as an inexpensive alternative to a diamond. Note that these are completely different materials.

Zoisite
Zoisite (Calcium-aluminum silicate) is a gray-green mineral that occurs in cracks of igneous rock. Zoisite has three known forms: anyolite (a green matrix containing rubies), tanzanite (transparent, blue-violet containing strontium), and thulite (opaque pink crystals containing manganese). Zoisite was named for the Slovenian mineral collector Baron Sigismund Zois von Edelstein, who financed the expedition that discovered Zoisite.