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AB stands for Aurora borealis (which means "northern lights"). Aurora borealis rhinestones have a special iridescent finish that shines with many colors. The iridescent surface is a result of a very thin layer of metallic atoms that have been deposited on the lower surface of the stone. This process was invented in 1955 by the Swarovski company together with Christian Dior.


Abalone is a mollusk whose shell is iridescent on the inside. Abalone is a source of mother of pearl, which is used in jewelry making.


Fashion accessories and their jewelry counterpart referred to as costume jewelry are items that used as fashion's complementary. Accessories help to bring up the spot that one wants to highlight in a dress or apparel.


Acroite is a rare, colorless variety of tourmaline.


Acrylics are a type of thermoplastic, and include transparent and opaque in varied colors. Some commonly-known acrylics are Lucite and Plexiglas. The bangle above is made of confetti Lucite.


Adamantine means having a luster like that of a diamond.


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.


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.


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 dendrite 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.


African jade (also called Transvaal jade) is a misnomer for massive green grossular garnet that is mined in South Africa; it is not jade, but does look like jade. It can be light green, white, or pink


Alexandrite is a mineral (a type of chrysoberyl) that appears to be different colors depending on whether it is viewed in natural or artificial light. Alexandrite appears to be red when seen in candle light and blue to green when seen in fluorescent light. Alexandrite was discovered on the birthday of the Russian Czar Alexander II, and it was named in his honor. Alexandrite is 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.


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.


An alloy is a combination of two or more metals. Common alloys used in jewelry are: gold under 24 Kt (mixed with silver, copper, and/or other metals), sterling silver (92.5% silver, 7.5% copper), brass (roughly half copper, half zinc), bronze (at least 60% copper with tin and perhaps other metals), and pewter (tin, lead, antimony, and a bit of silver or copper).


Almandine is a type of violet-tinged variety of garnet that ranges in color from deep red to reddish-brown. Almandine is the most common kind of garnet. Star garnets are almandine that exhibit an asterism. Almandine has a hardness of 7.5 and a specific gravity of 3.85-4.20.


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.


Amber is translucent fossilized tree resin (from conifers), a natural hydrocarbon that comes in many colors, including yellow, reddish, whitish, black, and blue. Amber is flammable. Rubbing amber produces static electricity. The word electricity comes from the Greek word for amber, "elektron." It used to be thought that amber possessed magical powers that protected the wearer from evil. Pressed amber consists of small pieces of amber that have been fused together to form a larger piece. Fake amber is easily made from plastics, and buyers must beware of cheap imitations sold as natural amber. Amber has a hardness of 2.5 and a specific gravity of 1.05-1.10.


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


Amethyst (Greek for "not drunken") is a form of the mineral quartz, and is a relatively common gemstone. Amethyst is usually purple, but can range in color from pale lavender to a very deep, reddish purple to a milky color to green. Deeper-colored amethysts are more highly valued. The ancient Greeks believed that amethyst made one immune to the effects of alcohol. Synthetic amethysts are hard to distinguish from the real stone.


Ametrine is a variety of quartz, a mixture of amethyst and citrine. Ametrine is partially purple and partially orange-yellow.


Amorphous means without form. An amorphous gem, like jet, amber, or ivory, does not have a regular internal structure, like those gems that fall within the seven crystal systems.


An amulet is a protective charm that is worn. It is worn in the hope of protecting the wearer from evil or illness or to bring the wearer good luck.


Angelite (CaSO4); it is a pale blue variety of calcium sulfate = anhydrate (it is gypsum that has lost water and crystallized). The stone is quite brittle; crystals are transparent to translucent. 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.


Anodized metal 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 (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 colorful surfaces.


Apache tears (a type of obsidian) 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 form of obsidian is found in lava flows in the southwest USA. Obsidian is formed when viscous lava (from volcano's) 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.


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 just about 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 range in color from honey-colored to pale reds, blues and greens to clear or white. It forms hexagonal crystals, pyramidal crystals, chisel shaped crystals, and other shapes. Aragonite has a hardness of 3.5-4 (relatively soft) and a specific gravity of 2.9 g/cm3.(average). Its chemical composition is CaCO3 (it is 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.


An 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, USA (near Anchorage).


Arkansas stone is an abrasive used in jewelry making. It is used to smooth metals.


Art Deco was a style popular from the mid-1910's until the mid-1920's. 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 Modern.


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.


A highly-skilled craftsman who exhibits great manual dexterity.


Arts and Crafts was an artistic movement that produced hand-crafted pieces toward the end of the 1800's. Pieces purposely look hand-made, incorporating hammer marks and simple cabochon settings. The Arts and Crafts movement also revived the art of enamel.


An 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.


Joseph Asscher was 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.


An asterism is a star-like luminous effect that reflects light in some gemstones, like star.


An 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 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.


Aventurine quartz is a type of quartz that has sparkling flecks (inclusions) of mica or iron. These colors of this stone 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.


The Japanese name for abalone pearls is Awabi pearls.


Axinite is an unusual, lustrous stone that is brown, yellow, blue, green or gray. Violet axinite is rare (and from Tasmania). 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.


An 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 (relatively soft) and a specific gravity of 3.7 to 3.9. Azurite is found in massive monoclinic crystals in Australia the southwestern USA, 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.
Articulated: Jewelry fashioned with hinges to provide movement and flexibility.

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


A baguette cut is a stone (usually a diamond) that has been cut into a long, rectangular shape. Baguette means "stick" or "rod" in French.


Bakelite (also called catalin) is a dense, synthetic resin that was used to make jewelry, game pieces, and many other things. Bakelite was patented by L.H. Baekeland in 1907. Bakelite plastic is made from carbolic acid and formaldehyde. Bakelite pieces are molded, extruded, or carved. When one Bakelite color is inlaid into another, interesting designs like polka dots can be made. Bakelite was first used to imitate amber. The bangle above is "butterscotch" bakelite


A bail is a triangular finding that attaches a pendant to a necklace.


A band is a ring that is made from a thin, flat, ribbon-like strip of material (usually metal). The band can be unadorned or decorated. Wedding rings are often bands.


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


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


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.


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


Baroque is a term that refers to irregularly-shaped stones or pearls.


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


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


A barrel clasp is a jewelry fastener that resembles a barrel. The two pieces of this clasp screw together. It is used to attach two other rings or links of a necklace or bracelet.


A barrette is an ornament worn clipped into the hair.


Base metal refers to non-precious metals. Base metals include copper, zinc, tin, and lead. 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.


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


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


Beads are small objects, each with a hole through it for stringing. Beads are made of glass, stones, wood, plastics, seeds, and ceramics.


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.


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 strongly diachronic; 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).


Beryls are a family of gemstone that include emerald, aquamarine, beryl (green), red, morganite (yellow), and heliodor (pink). 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).


A surface that has been cut at an angle less than 90 degrees.


The bezel is the part of a cut stone that protrudes above the edge of a setting. The bezel is also known as the crown.


A bezel setting is a way of setting a stone in which the stone is held by a band of metal around the outside of the stone.


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


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.


In the 1930's, the British and U.S. jewelry industries assigned stones to the months of the year as follows: January - Garnet February - Amethyst March - Aquamarine April - Diamond May - Emerald June - Pearl or Moonstone July - Ruby August - Peridot September - Sapphire October - Opal November - Topaz or Citrine December - Turquoise or Zircon


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 is gold jewelry that is made (but not always mined) in the Black Hills area of South Dakota, USA. Gold was first discovered in that area about 1874 by Horatio N. Ross. E.O Lampinen opened the Black Hills Jewelry Manufacturing Company in Deadwood, South Dakota in the early 1900's. Modern day Black Hills jewelry often has a three-color (yellow gold, pink gold and green gold) grape leaf and vine pattern. There are many companies that make Black Hills jewelry today, but by law, their creations must be made from Black Hills gold. This jewelry is often (but not always) 10 Karat gold.


Black moonstone is a type of labradorite and not true moonstone.


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


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


Bloodstone (also called heliotrope) is an inexpensive type of chalcedony that is green with red highlights (caused iron oxide). Bloodstone is porous and relatively soft.


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


A bodkin is a heavily jeweled, Renaissance era hairpin.


A "Bohemian diamond" is not a diamond at all, it is actually a rock crystal.


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


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


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 have an enhanced appearance.


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 yellowish color.


A bookchain is a metal chain with rectangular links of folded metal, each of which looks like a little book. This style dates from the Victorian Era, when these chains held lockets.


Bort is a term for industrial grade diamonds.


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).


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.


A bracelet is an ornament worn wrapped around the wrist. Types of bracelets include solid and hinged bangles, expansion, cuff, beaded, charm bracelets, Yurman-style and, and link bracelets.


Brass is a metal alloy containing (at least 50%) copper and zinc.


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


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.


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


A brooch (also called a pin) is an ornament that can be pinned to a garment.


Bronze is a metal alloy containing (at least 60%) copper plus tin and other metals.


A brushed finish on a metal's surface is made by rubbing a stiff metal brush across the surface of jewelry, slightly reducing the metal's reflectivity.


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


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.


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


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.


When the gemstone is held in place without the use of prongs or beads and is set flush with the setting’s surface.

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