ANGELITE is a pale blue variety of calicium sulfate = anhydrate (it is gypsum that has lost water and crystallized). The stone is quite brittle; crystals are transparent to transluscent. Angelite stone has a hardness of 3 to 3.5 (quite soft) and a specific gravity of 2.9 - 3.0.
ANGELSKIN CORAL is a pale pink coral, from deep sea coral. Angelskin coral is one of the most valued colors of coral (red is also highly prized). 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. 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.
ANNEALING is the process of heating a metal and then cooling it to make it more workable. As metal is worked (hammered, rolled, etc.), stresses make the metal brittle (the metal molecules are pulled into random structures during the working). Annealing the metal make the metal re-crystallize, putting the molecules in an orderly structure. The temperature (and amount of time it takes) for annealing a metal depends on what metal or alloy it is. Large pieces are annealed in an annealing oven; small pieces are annealed using a blow-torch.
ANNIVERSARY BAND is a ring which features gems going partially or completely around the circumference. A traditional anniversary gift, it usually matches the wedding ring set. ETERNITY BANDS are often used as anniversary bands.
ANODIZED is a term describing metal that has been through an electrochemical process which changes the molecular structure of the surface layer, giving it a thin, protective film. In the anodization process, the metal is placed in an acid bath at the "anode" or positive end of the electrical circuit and an electrical current is passed through the tank. This process causes a controlled oxidation of the metal's surface to occur in which oxygen atoms bond to surface atoms of the metal. Aluminum is often anodized, as is magnesium, titanium and tantalum. Anodized metal has a lustrous sheen, the anodizing process can produce a variety of colorful surfaces.
ANTIQUE JEWELRY is authentic jewelry from past eras.
APACHE TEARS is a type of obsidian, a volcanic glass. It is usually black and occasionally red, brown, gray, green (rare) with "snowflakes," or may be clear. This glassy, lustrous form of obsidian is found in lava flows in the southwestern United States. Obsidian is formed when viscous lava from volcanoes cools rapidly. Most obsidian is 70 percent silica. Obsidian has a hardness of 5 and a specific gravity of 2.35.
AQUAMARINE is a transparent, light blue or sea-green stone that is porous. Today, blue aquamarines are more highly valued, but this was not true in the past, when sea-green stones were prized. Heat treatment turns greenish stones bluer. The best aquamarines come from Brazil. Large aquamarines are relatively common. Aquamarines are usually faceted, but when they are cabochon cut, a cat's eye effect or asterism may appear. Aquamarines belong to the beryl family of stones. Aquamarine has a hardness of 7.5-8 and a specific gravity of 2.65-2.85.
AQUA REGIA is a 3:1 mixture of hydrochloric acid and nitric acid. Aqua regia is used to test gold and platinum. It is one of the few substances that can dissolve gold and platinum.
ARAGONITE is a mineral that is rarely used for jewelry. It is transparent to translucent and can ranges in color; honey-colored, pale red, blue, green, clear or white. It forms hexagonal crystals, pyramidal crystals, chisel-shaped crystals and other shapes. Aragonite has a hardness of 3.5-4 which is relatively soft and a specific gravity of 2.9 g/cm3. Its chemical composition is CaCO3, a form of Calcium Carbonate. Aragonite is named for Aragon, Spain where it was first found in 1790. Aragonite is also found in many other European, North African and some North American locations.
ARCADE SETTING, also called coronet or claw setting, is one in which the stone is held in by many metal claws around a metal ring.
ARCTIC OPAL is a blue-green stone that is a mixture of azuritea and malachite; it is not a type of opal at all. Arctic opal is mined in the Wrangle Mountains and the Chugach Mountains of Alaska, near Anchorage.
ARKANSAS STONE is an abrasive used in jewelry making, used primarily to smooth metals.
ART DECO was a style popular from the mid-1910s until the mid-1920s. This style originated in Paris, France. Art Deco pieces are characterized by geometric lines and angles, with very few curves. This art movement eventually became bolder and evolved into Art Moderne.
ART NOUVEAU was a style popular from roughly 1895 until World War I. Art Nouveau pieces are characterized by curves and naturalistic designs, especially depicting long-haired, sensual women. Louis Comfort Tiffany made archetypal Art Nouveau pieces.
ARTS AND CRAFTS was an artistic movement that produced handcrafted jewelry toward the end of the 1800s. The jewelry purposely looks handmade, incorporating hammer marks and simple cabochon settings. The Arts and Crafts movement also revived the art of enamel.
ASSAY is a test of the purity of an alloy. A tiny piece of metal is scraped from the piece and the percentage of gold or silver is determined. Official assay offices determine whether a piece qualifies for an appropriate hallmark.
ASSCHER CUT, was named after Joseph Asscher, an eminent diamond cutter who cut the 3,106 carat Cullinan diamond. Asscher worked in Amsterdam. In 1902, his company, the Asscher Diamond Co., developed and patented the Asscher cut, a squarish step cut with an almost octagonal outline. This new cut enhanced the fire and light of the stone; it had a small table, a high crown, wide step facets, a deep pavilion and square culet. This cut became very popular in Art Deco jewelry and was a forerunner of the emerald cut. Recently, the Royal Asscher Diamond Co. resumed production of the original Asscher cut diamonds.
ASTERISM is a star-like luminous effect that reflects light in some gemstones, like star.
AUSTRALIAN RUBY is actually a pyrope garnet and not a ruby at all.
AVENTURINE FELDSPAR is also called Sunstone, a variety of oligoclase. This gemstone varies from golden to orange and reddish-brown, and can be transparent or translucent. Sunstone is metallic-looking due to sparkling red, orange or green crystalline inclusions composed of hematite or goethite crystals. Sunstone is found in Canada, Oregon in the United States, 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.
AVENTURINE QUARTZ is a type of quartz that has sparkling flecks, or inclusions, of mica or iron. Its colors include red-brown, yellow, gray and green. Aventurine quartz has a hardness of 7 and a specific gravity of 2.64-2.69. This stone is usually cut with a flat or rounded surface to maximize its sparkle. Aventurine quartz is found in India, Russia and Tanzania.
AWABI PEARL is the Japanese name for abalone pearls.
AXINITE is an unusual, lustrous stone that is brown, yellow, blue, green or gray. Violet axinite from Tasmania is rare. It has both transparent and translucent varieties. Axinite is dichroic. Axinite has a hardness of 7 and a specific gravity of 3.3. Axinite is a boro-silicate of aluminum and calcium. It is used only as a mineral specimen and not in jewelry.
AXIS OF SYMMETRY, also called a rotational axis, is an imaginary line around which an object can be rotated a certain number of degrees and look like the original shape. When two planes of symmetry intersect, they form a straight line, which is an axis of symmetry.
AZURITE is a beautiful copper-based blue mineral that is often used in jewelry. The color ranges from very deep blue to pale blue. Azurite has also been used as a dye for paints and luxury fabrics. Azurite is hydrated copper carbonate; its chemical formula is Cu3 (CO3)2(OH) 2. Malachite, another copper-based mineral, and azurite are often found together. Azurite has a hardness of 3.5 to 4 which is relatively soft and a specific gravity of 3.7 to 3.9. Azurite is found in massive monoclinic crystals in Australia, the southwestern United States, France, Mexico, Morocco, Namibia, Zaire and Europe. Azurite is sometimes coated with a colorless wax or impregnated with plastic in order to enhance the color and increase the hardness.
Crystal Enchantments: A Complete Guide to Stones and Their Magical Properties
