A gemstone is a piece of mineral crystal which, when cut or polished, is used to make jewelry or other adornments. However, certain rocks and occasionally organic materials that are not minerals are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity and notoriety are other characteristics that lend value to gemstones.
Gemology or gemmology is the science dealing with natural and artificial gemstone materials. It is a geoscience and a branch of mineralogy. Some jewelers are academically trained gemologists and are qualified to identify and evaluate gems.
Tanzanite is the blue and violet variety of the mineral zoisite, caused by small amounts of vanadium. Tanzanite belongs to the epidote mineral group. Tanzanite is only found in Simanjiro District of Manyara Region in Tanzania, in a very small mining area approximately 7 km (4.3 mi) long and 2 km (1.2 mi) wide near the Mererani Hills.
A chemically pure and structurally perfect diamond is perfectly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impurities and/or structural defects in the crystal lattice. Depending on the hue and intensity of a diamond's coloration, a diamond's color can either detract from or enhance its value. For example, most white diamonds are discounted in price when more yellow hue is detectable, while intense pink diamonds or blue diamonds can be dramatically more valuable. Of all colored diamonds, red diamonds are the rarest. The Aurora Pyramid of Hope displays a spectacular array of naturally colored diamonds, including red diamonds.
Demantoid is the green gemstone variety of the mineral andradite, a member of the garnet group of Minerals. Andradite is a calcium- and iron-rich garnet. The chemical formula is Ca3Fe2(SiO4)3 with chromium substitution as the cause of the demantoid green color. Ferric iron is the cause of the yellow in the stone.
Diamond enhancements are specific treatments, performed on natural diamonds, which are designed to improve the visual gemological characteristics of the diamond in one or more ways. These include clarity treatments such as laser drilling to remove black carbon inclusions, fracture filling to make small internal cracks less visible, color irradiation and annealing treatments to make yellow and brown diamonds a vibrant fancy color such as vivid yellow, blue, or pink.
The Gemological Institute of America (GIA) is a nonprofit institute based in Carlsbad, California. It is dedicated to research and education in the field of gemology and the jewelry arts. Founded in 1931, GIA's mission is to protect buyers and sellers of gemstones by setting and maintaining the standards used to evaluate gemstone quality. The institute does so through research, gem identification and diamond grading services and a variety of educational programs. Through its library and subject experts, GIA acts as a resource of gem and jewelry information for the trade, the public and media outlets.
The American Gem Society (AGS) is a trade association of retail jewelers, independent appraisers, suppliers, and selective industry members, which was founded in 1934 by Robert M. Shipley.
Diamonds were largely inaccessible to investors until the recent advent of regulated commodities, due to a lack of price discovery and transparency. The characteristics of individual diamonds, especially the carat weight, color and clarity, have significant impact on values, but transactions were always private. With the standardized commodity as an underlying asset, several market traded financial instruments have been announced.
The Asian Institute of Gemological Sciences (AIGS) is a private gemological school and gemological laboratory based in Bangkok, Thailand.
Martin Rapaport is chairman of the Rapaport Group, founder of the Rapaport Diamond Report and the RapNet online diamond trading network. Rapaport has been called a "maverick" within the diamond industry for standardizing and publishing diamond prices. He has also been criticized for non-transparency in his methodology, as well as his silence over a corruption scandal involving the GIA, with which he has strong ties. Rapoport was an early proponent of the Kimberley Process aimed at limiting the number of "conflict diamonds" in worldwide circulation.
Diamond is one of the best-known and most sought-after gemstones. They have been used as decorative items since ancient times.
A birthstone is a gemstone that represents a person's period of birth, which is usually the month or zodiac sign. Birthstones are often worn as jewelry or as a pendant necklace.
Richard T. Liddicoat, Jr. was an American gemologist. Liddicoat was an educator in gemology, who made contributions in the area of diamond quality grading and gem identification. Liddicoat was the Chairman of the Board of Governors at the Gemological Institute of America (GIA).
Richard W. Hughes is an American gemologist and author, known as an authority on corundum, rubies and sapphires.
WD Lab Grown Diamonds ("WD") was a market leader in Chemical Vapor Deposition (CVD) diamonds, headquartered in the Washington, D.C. area. Founded in 2008, WD produces lab-grown diamonds for distribution under the brands, in addition to creating diamonds for high-tech Advanced Materials applications.
Worthy.com is an online liquidation marketplace for pre-owned luxury goods including diamonds, brand-named watches, and diamond jewelry. Worthy is headquartered in New York City and was founded by investment banker Ben De-Kalo in 2014.
Gem & Jewellery Export Promotion Council (GJEPC) is an organisation set up by the Government of India (GOI) with aim to promote the Indian gem and jewellery industry and its products.
Gemological Science International, or GSI, is an independent gemological organization that is one of the largest gemological entities in the world, with offices in four continents.
Larisa Popova is an Italian gemologist, appraiser and jeweler.
