Agate to Zircon

Adularia is a variety of orthoclase feldspar that is colorless to milky in appearance. It is mineralogically a potassium, aluminum, silicate feldspar found ...
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Agate is a variety of chalcedony found in many different colors and degrees of translucency. There are several varieties of ...
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Alabaster is a name used for gypsum and calcite but has also been used to indicate selenite. These minerals are easily worked ...
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Alexandrite is a variety of chrysoberyl with a distinct change of color when viewed in incandescent and fluorescent light. The ...
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These deep purplish-red garnets were often featured in Victorian Jewelry. When they are cut en cabochon they are referred to as "carbuncles." For more ...
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Amazonite, a variety of the microcline series of the feldspar group, gets its name from the Amazon River. A gridlike structure visible in ...
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In the forest primeval, a creature calls…Its echo is heard for millions of years.Frozen in time; the drama unfolds--A death ...
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Amethyst is the most coveted member of the quartz family. It can be found in shades ranging from a very ...
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Ametrine is a variety of quartz consisting of both amethyst and citrine with zones of both purple and yellow. Most ...
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Andalusite var. Chiastolite. Gems & Gemology: The Quarterly Journal of the Gemological Institute of AmericaAndalusite:Winter 1948, An 85 ct. Rough Andalusite ...
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Andradite Garnet var. Demantoid ...
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Gems & Gemology: The Quarterly Journal of the Gemological Institute of AmericaApatiteSummer 1962, Cat’s-Eye Apatite, p. 315, 2pp.Summer 1963, Yellow Cat’s-Eye ...
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Aquamarine is the blue variety of the mineral beryl. Most natural aquamarine is a pale bluish green, which was the ...
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Aragonite is a naturally occurring crystal form of calcium carbonate and is a precipitate from salt and freshwater conditions. One ...
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Aventurescence is a phenomenon in gemstones whereby glittering reflections of small inclusions of hematite or goethite in feldspar or fuchsite ...
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Aventurine Quartz Rough ...
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Gems & Gemology: The Quarterly Journal of the Gemological Institute of America.Azurite:Fall 1960, Azurite and its Absorption Spectrum, p. 71, 1p ...
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Sources Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 22-23. Schumann, Walter. Gemstones of the World, New ...
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Gems & Gemology: The Quarterly Journal of the Gemological Institute of America.Benitoite:Summer 1953, Benitoite, by Ehrmann, p. 317, 1p.Summer 1963, A ...
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Beryl is a beryllium aluminum silicate that occurs in every color of the rainbow but is colorless in pure form; ...
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Biwa pearls are a cultured pearl produced in a freshwater mussel native to Lake Biwa, Japan. Considered to be a non-nucleated pearl, they are ...
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Bloodstone Intaglio Signet Ring with a Coat of Arms Seal. Tiffany & Co.  Who on this world of ours his ...
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Cairngorm is the name given to a citrine quartz variety with an amber or brown color traditionally mined in the Cairngorm Mountains in ...
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Calcareous concretions are pearl-like growths produced in mollusks that lack nacre. While still composed of calcite and aragonite, the crystals are much coarser. Some ...
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Sources Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 41-43. Schumann, Walter. Gemstones of the World, New ...
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Calcium carbonate is a primary component of the shells of marine mollusks and pearls. The outer shells of mollusks are ...
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A large almandine garnet that is cut en cabochon. These deep purplish-red garnets were popular in Victorian jewelry ...
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Carnelian Intaglio Ring. Carnelian (or cornelian) is the translucent red variety of chalcedony which in its turn is a form of cryptocrystalline quartz. It's been known ...
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Cave pearls are not actually pearls, they are a calcareous concretion occurring in subterranean limestone caves. While they bear a resemblance to pearls, ...
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Chalcedony is cryptocrystalline quartz. It is semitransparent to opaque and, depending on its color, chalcedony is further divided into several varieties. History ...
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Chlorastrolite. Sources Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 49-50 ...
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Chrysoberyl is among the most brilliant of gems and its hardness is only surpassed by diamonds and corundum. The name ...
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Chrysocolla is an intense blue-green to light blue variety of chalcedony. It can be translucent to semitransparent and is usually cut en cabochon. Tumbled ...
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Chrysoprase is the name reserved for bright green cryptocrystalline quartz. It is a subvariety of chalcedony and owes its beautiful green color to the ...
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French Japonesque Cinnabar, Diamond and Onyx Jabot Pin.  Online Texts on CinnabarSome Cinnabar Deposits in Western Nevada by Knopf ...
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Citrine is a yellow or golden variety of quartz, colored with iron. Natural citrine is relatively rare, occurring in Brazil, ...
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Conch Pearls A conch pearl is not technically a pearl at all, but a white or pink (sometimes brown or yellow), non-nacreous, ...
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Copal is a fossilized organic resin. This amorphous yellow to brownish material is often confused with amber, but amber is much ...
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Coque de perle, from the French for 'pearl shell' was a Georgian faux pearl carved from the East Indian nautilus ...
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Coral is one of a very few organic gemstones. It consists of a mass of skeletons of tiny marine invertebrates ...
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Definition The mineralogical name for Al2O3, the corundum family encompasses the gem varieties sapphire and ruby. It crystallizes in the trigonal structure and ...
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Round Brilliant-Cut Cubic Zirconia. Cubic zirconia is a man-made material used to imitate diamond and other gemstones, commonly referred to as CZ. Cubic ...
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Antique Demantoid and Diamond Earrings. At the end of the reign of Nicholas I, Emperor of Russia, and the beginning ...
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Diamonds are valued for their incredible brilliance and hardness. Diamonds are chemically pure carbon, identical to the graphite used for ...
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Grossular Diopside. Photo Courtesy of Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 ...
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A surface covered with small projecting crystals, usually lining the sides of a cavity ...
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Emerald is the green variety of the mineral beryl, owing its vibrant color to a trace amount of chromium and ...
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Epidote Crystals. Photo Courtesy of Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 ...
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Feldspar var. Moonstone. Feldspar is a gem group that includes microcline, orthoclase, and plagioclase varieties. Each variety varies as to ...
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Fire Agate is an iridescent brown form of chalcedony. Fire Agate ...
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Fool's gold is the popular name for pyrite. Pyrite looks like gold but is hard and brittle and lacks the malleability of gold. Fool's Gold aka ...
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The term garnet applies to a group of minerals with six main varieties. The varieties differ in chemical composition and ...
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Gadolinium Gallium Garnet. A synthetic gemstone used as an early diamond substitute. GGG is manufactured by the Czochralski method and ...
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Most glass is a man-made material sometimes used to simulate a gemstone. In that case, it's called paste. There are also three ...
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Tsavorite 1967 - Discovered in Northern Tanzania close to the Kenyan border by Campbell R. Bridges. Mining the deposit wasn't ...
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The Sri Lankan gueda sapphire is a pale, translucent and, until the discovery of heat treatments, useless variety of sapphire ...
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Finely Carved Hardstone (Sardonyx) Cameo Brooch. Hardstone is a term used loosely to refer to any hard gem material used ...
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Hematite derives its name from the Greek word haema for blood. Thinly sliced hematite is a reddish color and, when rubbed against ...
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Hiddenite is the strongly pleochroic, bright green variety of spodumene. First discovered in North Caroline by W. E. Hidden in 1879. Sources ...
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Horn, commonly used in buckles, brooches, combs and hair ornaments was usually ox-horn, although it could be from any animal. With ...
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In the fall of 2009 Stone Group Labs received an unusual item for identification. It turned out to be manufactured ...
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Hornblende is a series of minerals, not a mineral in its own right. By composition, it is an iron-magnesium silicate that ...
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A polycrystalline mineral in the garnet group that occurs in a green or pink color, sometimes intergrown with idocrase. Bright green samples are sometimes used ...
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Idocrase is mineral species known as Vesuvianite and has several varieties. Sometimes erroneously referred to as "California Jade." Californite - ...
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Paste Used to Imitate Yellow Natural Gemstones in Costume Jewelry. An imitation is an object or gemstone which is used ...
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Etymology The name, iolite, originates from the Greek word “iodes” meaning violet. It is often found under the misleading name ...
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Historically, this organic gem material referred to as Ivory came only from elephant tusks. Since elephants have become a protected ...
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Jade is in the gemstone family that includes both Jadeite and Nephrite. The term Jade is still often interchanged with jadeite and nephrite ...
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Jadeite is a silicate containing sodium and aluminum. Jadeite occurs in a very wide range of colors, translucencies and textures ...
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Jasper Cuff Links. Jasper is a member of the chalcedony family of gemstones. The name is of Greek derivation meaning spotted stone ...
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A Jet Box with a Pietra Dura Inlay. Jet is a type of brown coal used since the Stone Age ...
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Kashmir Sapphire and Diamond Ring. Undoubtedly, the rarest and most beautiful of all sapphires are the legendary Kashmir. As befitting such otherworldly ...
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Kunzite and Diamond Ring. Kunzite, a variety of spodumene, was named for George F. Kunz who was the first to describe ...
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Labradorite is a mineral species of the plagioclase series of the feldspar group. Egyptian Revival, Victorian Scarab Brooch, c.1870 ...
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Lapis lazuli is a rock aggregate made up from - predominantly - the minerals lazurite, sodalite, nosalite and hauyne. It ...
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Malachite is green stone with irregular bands of lighter and darker green. The name malachite comes from the Greek word malache which ...
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Majorica is a brand name of a high-quality pearl simulants produced on the Spanish island of Majorica at the Majorica S.A. company ...
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Marcasite is an iron sulfide mineral with an orthorhombic crystal structure. It is very brittle and unsuitable for jewelry. What ...
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Fire opal refers to the variety of transparent red, orange or orangy-red opal usually lacking play-of-color. Fire opal is cut en cabochon as ...
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Amazonite in Albite Specimen. Photo: Rob Lavinsky, iRocks.com Microcline is a mineral series in the feldspar group. Amazonite is a light green ...
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Moldavite is formed from melted rock resulting from a meteorite strike. The surface of these small specimens can be rippled ...
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Tiffany Iris Corsage Brooch Set With Montanna Sapphires. © The Walters Art Museum. While most are familiar with the exotic ...
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Moonstone is a variety of orthoclase feldspar, which is a sodium aluminum silicate. Moonstones can occur colorless, blue-white, white and ...
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Early 20th Century Moss Agate Match Safe. Moss agate is a translucent chalcedony with green moss-like inclusions, usually hornblende. When the hornblende oxidizes, the color ...
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Mother-of-pearl a nacreous, lustrous, iridescent lining of the shell of a mollusk that can be carved and cut for jewelry ...
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Nephrite Nephrite is a magnesium and calcium silicate with an interlocking fibrous structure that gives it extreme toughness. It is ...
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Obsidian. Obsidian is a naturally occurring glass of volcanic origin, having an amorphous structure due to rapid cooling. It can ...
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Oligoclase is a mineral species of the plagioclase series of the feldspar group ...
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Onyx is a variety of cryptocrystalline silicon dioxide or chalcedony. It is banded with contrasting colors making it an excellent ...
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Opal is a hydrous variety of silicon dioxide. It is unlike other minerals because it is not crystalline! Opal is ...
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Opaline glass was a gem imitation with a milky white to blue appearance generally cut en cabochon a popular daytime "gem" in ...
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Orthoclase is a mineral series in the feldspar group. Moonstone Art Nouveau Orthoclase Feldspar (Moonstone) Pendant. Sources Gem Reference Guide, Los Angeles: ...
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Paraiba Tourmaline and Diamond Ring and Earrings.Photo Courtesy of Christie's. Paraiba is a tourmaline variety noted for its neon blue and green ...
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Pearls are organic gems, produced in pearl oysters. Pearl oysters are not edible, and edible oysters do not produce gem ...
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Peridot is the gem variety of the mineral chrysolite or olivine. It is a silicate of iron and magnesium found ...
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Petrified Wood is is wood that has been replaced by chalcedony aka silicified wood. In looks, it is very similar to patterned ...
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Plastics are man-made substances used in jewelry to imitate natural gem materials. Early plastics were organically derived, like the combination ...
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A leek green colored cryptocrystalline quartz aggregate with actinolite inclusions. Usually darker and less saturated than chrysoprase. In Greek the word Prason means leek, hence the name ...
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Prasiolite is the green variety of Quartz. The material is extremely rare in nature and is only found in a handful ...
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Pyrite is an opaque yellow mineral with a metallic luster. Its cubic crystal system is evident in its outward appearance and specimens are ...
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For over 600 years, the so-called 'Bohemian Garnets' from the Czech Republic amass the bulk of pyropes used in jewellery ...
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A quahog is a bivalve clam native to the eastern seaboard of the United States. Used mostly as a food ...
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Quartz is a commonly occurring variety of silicon dioxide. It often crystallizes into well-formed hexagonal prisms. Quartz occurs in many ...
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Rhinestone is the name given to rock crystal which is faceted to imitate diamond. It is also a name for ...
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Rhodochrosite is a manganese carbonate mineral with a transparent to translucent rose-pink color with undulating bands of white, gray or ...
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Rhodonite is a translucent to opaque pink to reddish color gemstone with patches or veins of black throughout. Usually cut en cabochon or drilled ...
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Natural Color-Change Sapphire, Rock Crystal and Diamond Pendant. The Greek word krystallos meaning "ice", provides the basis for the origin of the ...
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Rose quartz gets its name from its rosy pink color. Because of its massive turbid crackled nature rose quartz is ...
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Ruby is the red variety of sapphire or the mineral corundum. When corundum occurs in any color, other then red, ...
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Sapphire is a variety of the mineral corundum that occurs in spectacular colors with great durability and stability. When corundum ...
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Sard is a translucent to semi-transparent variety of chalcedony. The colors are similar to carnelian but they are darker and less ...
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Sardonyx is a brown and white banded variety of onyx primarily used in glyptography. Antique Victorian Sardonyx Seal Fob. SourcesGem Reference Guide, Los ...
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Saussurite is a rock formed from green zoisite in combination with epidote, white feldspar and other minerals ...
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Seed pearls are very small; less than a one-quarter grain in weight, smaller than 2mm in size and off-round in shape. Historically they occurred ...
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Serpentine is not a single crystal gem, but a rock-forming mineral group. The name may derive from the Latin serpentinus due to ...
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A fissile (easy to split) sedimentary silicate-rich rock with particles mostly in the silt and clay size. The color is ...
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Shell is the organically formed hard outer part of a saltwater or freshwater animal. Shells of all types have been ...
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Smoky Quartz is a brownish black to greyish color variety of quartz. Cairngorm is the Scottish term for smoky quartz Sources Gem ...
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Cut Spessartite from Loliondo, Tanzania.Image by Tim Spauwen Spessartine was first discovered in the Spessart Mountains of Germany from which ...
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Spinel is a magnesium aluminum oxide, occurring in many colors with excellent durability. Natural spinel is really a group of ...
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The name spodumene derives from the Greek meaning burnt to ashes describing the non-gem colorless or gray variety of spodumene. There are ...
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External LinkHistory of Synthetic Corundum: http://www.dtic.mil/dtic/tr/fulltext/u2/a460239.pdfGems & Gemology: The Quarterly Journal of the Gemological Institute of America.Synthetic Corundum:Fall 1939, Lined Foil Back ...
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Tanzanite is a variety of blue zoisite that was discovered in the Merelani District of Tanzania in 1967. It's compelling ...
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SourcesGem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 262-264.Schumann, Walter. Gemstones of the World, New York: Sterling ...
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Tiger's-eye is chatoyant quartz. It ranges in color from brownish yellow to brown or reddish brown with iron oxide being the ...
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Topaz is an aluminum, hydroxyl-fluorine silicate, found primarily in gem pegmatites. Minas Gerais in Brazil is the largest producer of ...
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Tortoise Shell Locket and Chain. Tortoise shell is the name for the outer blades covering the upper shell of the ...
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Tourmaline is a group of minerals displaying the widest variety of gemstone color in the mineral kingdom. The spectral assortment ...
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A trapiche emerald is one with a central green area radiating six green arms giving the gem a flower-like appearance. These intense green ...
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Turquoise is chemically a hydrous copper aluminum silicate, occurring in microcrystalline nodules. It has been coveted and admired throughout our ...
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Through the eighteenth century and on into the middle of the nineteenth, Vauxhall glass was a popular gem substitute. Intense ...
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Auguste Victor Louis Verneuil (1856-1913) Auguste Victor Louis Verneuil is the father of gemstone synthesis. Born a watchmaker's son, Verneuil became a ...
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Zircon is a zirconium silicate that crystallizes in the tetragonal crystal system. It is highly dispersive and brilliant. Natural zircons ...
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Zoisite is named for the famed collector Sigmund Zois. Discovered in Austria in 1805 in the Sau-Alp mountains, zoisite was ...
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