Agate:  Form of chalcedony occuring in nodular masses in rocks such as volcanic lavas.  Wide variety of colors and patterns.  To clean your agate, avoid harsh detergents.  Wash with warm, soapy water and dry thoroughly.  Moh's scale of hardness:  6.5 - 7.

Alexandrite:  One of the most valuable gemstones due to its scarcity.  A chrysoberyl which contains iron, titanium and chromium which allows its color change from green/bluish green to red/purplish-red.  To clean your alexandrite, avoid harsh detergents.  Wash with warm, soapy water.  Ultrasonic and steam cleaning are usually safe.  Moh's scale of hardness:  8.5.

Amazonite:  Aqua colored feldspar which takes its name from the Amazon River.  Opaque pastel blue-green colors.  Thought to bestow truth, integrity and honor, enhance love, soothe tension.  To clean your amazonite, avoid harsh detergents.  Wash with warm, soapy water and dry thoroughly.  Never clean ultrasonically and never steam clean.

Amber:  Transparent to translucent fossil resin of the Pinus sacciferous tree, estimated at 50 million years old.  Very light in weight.  To test for genuine amber, you can stick a hot needle into an inconspicuous spot and it should smell like pine.  To clean your amber, avoid harsh detergents.  Wash with warm, soapy water and dry thoroughly.  Never clean ultrasonically.  Never steam clean.  Moh's scale of hardness:  2 - 3.

Amethyst:  Naturally occurring gemstone ranging in color from pale to deep purple.  The most valuable form of quartz.  Color is caused by iron and manganese compound impurities in the mineral. Thought to increase spiritual awareness.  To clean your amethyst, avoid harsh detergents.  Wash with warm, soapy water.  Ultrasonic cleaning is usually safe.  Never steam clean.  Moh's scale of hardness:  7.

Ametrine:  Unique stone combining both amethyst and citrine.  From the mountains of Brazil.  Said to aid meditation, relieve tension.

Antique:  Jewelry made before 1950.

Apatite:  Rare stone of translucent sea green.  Said to enhance intellect and foster unconditional love.

Applique:  Ornamental work made separately and then applied to an article.

Apple Juice Bakelite:  Colorless Bakelite (Prystal) was introduced by the Catalin Corp. in 1935.  It was carved on the backside with floral or figural designs that looked three dimensional from the front.  This is called "reverse carved".  Over time, the pieces have oxidized to a light amber color which is called "apple juice."

Aquamarine:  Naturally occurring gemstone in the beryl group.  Ranging in color from the palest of blues, whites and greens to a deeper blue.  Said to promote safe travel on water and create peaceful stillness.  To clean your aquamarine, avoid harsh detergents.  Wash with warm, soapy water.  Ultrasonic and steam cleaning are usually safe.  Moh's scale of hardness:  7.5 - 8.

Aragonite:  Golden colored stone with medium translucence said to foster truth and understanding.  A nurturing stone.

Art Deco:  Geometric lines, bold color.  1910-1930.

Art Nouveau:  More curving lines, designs representative of nature.  1890-1915.

Aurora Borealis:  Microscopic layers of different materials vacuum plated to glass for irridescence first made by the Swarovski Company in 1955.

Aventurine:  Translucent stone with metallic irridescence caused by small inclusions of fuchsite, a mica material.  The name is derived from the Italian word "aventura" which is a type of Italian glass. Thought to boost creativity.  To clean your aventurine, avoid harsh detergents.  Wash with warm, soapy water and dry thoroughly.  Never clean ultrasonically.  Never steam clean.  Moh's scale of hardness:  7.

Azurite:  Deep blue stone, often with inclusions of Malachite, Chrysocolla or Turquoise in areas of copper deposits.  Its name is thought to be derived from the Persian word lazhward or the Arabic azul - both of which mean blue.  In the Middle Ages and the Renaissance, it was ground into pigment for use as eyeshadow.  It was sacred to the Egyptians as an aid to spiritual communication.  Some believe it reduces anger and increases psychic awareness.  It is also believed to reduce abnormal cell growth and decrease the pain of rheumatism.  Moh's scale of hardness: 3-4.

Baguette:  A long narrow rectangular faceted stone.

Bail:  Loop through which a chain or cord passes.

Basse-taille:  (bas TIE yuh)  In enameling, decoration in which the design is carved at the bottom of a depression and shows through the transparent coat of enamel.

Bakelite:  Plastic invented in 1909 by Leo Headrick Baekeland.  It is a phenol plastic that can be cast.  Bakelite is the trade name for the Bakelite Corporation.  To test for genuine Bakelite, you can put a small amount of 409 cleaner on a cotton swab and rub the swab on the backside of your piece. (Do not clean the piece first!)  If the cotton turns yellow (even slightly) chances are that you have Bakelite.

Baroque:  In jewelry terms, this means irregular in shape.

Bas-relief:  Design that extends only slightly from the background, such as a cameo.

Belcher Mounting:  A kind of ring mounting with the setting claws or prongs formed in the shank of the ring.

Bezel Set:  Metal band with top edges burnished over to hold the stone in place.