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. All dvb 14K is at the 58.5% standard and is marked 585.

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

925
dvb marks its sterling silver 925, meaning 925 parts silver per 1000.

ACCESSOCRAFT
The Accessocraft Products Corp. is a company that produces costume jewelry, belts, buttons, and other accesories in a variety of styles. Accessocraft was founded in 1935 in New York, NY, USA.

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. manufacturer's 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 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 . 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 massiAmetrineve forms. It is a 7 on the Mohs scale of hardness.

Ametrine
This is a bi-color variety of quartz contining 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. amuletThe 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. asterismAsterism 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
aventurine cabochonAventurine 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. A azurite-malachiterelatively 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, Nambia, Zaire, and Europe.
Malachite, which is another copper-based mineral, is often found with azurite. When found together it is called Azurite-Malachite.