Gabrielle Cut | A "triple brilliant cut" with 105 facets developed by Gaby (Gabi) Tolkowsky in about 1997.
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GAGTL, G.A.G.T.L. | Gemmological Association and Gem Testing Laboratory of Great Britain. Now Gem-A.
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Gauge, Gauges | Any of various devices and instruments used to estimate the weight of diamonds, by measuring or estimating physical dimensions, such as diameter, depth, length. Some are better than others.
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GE, G.E. General Electric | In 1955 the GE Research Laboratory announced the invention of the first reproducible process for making diamonds, a process that became the basis for GE's man-made industrial diamond business, which today is one of the world’s major sources of industrial diamond abrasives. In 2000 GE Gem Technologies integrate high pressure / high temperature technology with knowledge of diamond structure to eliminate impurities and restore the color of rare high-purity diamonds, and market them as Bellataire Diamonds.
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Gem | Small article of great value or beauty, gemstone.
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Gem-A | Gemmological Association and Gem Testing Laboratory of Great Britain. Previously known as GAGTL, G.A.G.T.L..
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Gem Defensive Programme | Described by Wired (wired.com) as a none too subtle campaign to warn jewelers and the public about the arrival of manufactured diamonds.
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Gemesis | Manufacture and market "Gemesis Cultured Diamonds, based in Sarasota, Florida, USA.
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Gemmologist, Gemologist | A person with expertise in gemmology, a gemstone expert. There are formal qualifications, such as F.G.A. (Fellow of the Gemmological Association) in the UK.
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Gemstone | Any organic or inorganic mineral or material, excluding metal, which is used to decorative effect in jewellery. Some argue that only natural, rare or valuable items should be included
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GE POL | Laser inscription on girdle of HPHT treated diamonds marketed by General Electric Company and Pegasus Overseas Limited. The GE POL name was briefly changed to Monarch, and then to Bellataire in 2000.
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Gerald | Famous member of the Ratner family, became Managing Director of his family's established retail jewellery business, expanded it greatly, acquiring H. Samuel and others, but was blamed for the share price drop after his "total crap" and other comments. Now operates as geraldonline, and is believe to be subject to an agreement barring him from using the Ratner name.
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Getter, Nitrogen | A "nitrogen getter" is an agent to attract and absorb nitrogen when growing synthetic diamonds, to obtain colourless diamonds rather than yellow ones. Aluminium has proved to be effective.
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GIA, G.I.A. | The Gemological Institute of America. Styles itself as the world's leading authority on diamonds and other gemstones. Market leader for diamond and gem certificates by virtue of its location and size.
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GIA in Grading Scam |
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Gipsy, Gypsy Setting | The gypsy setting is a recessed setting in which the stone is sunk into the metal. There are often engraved designs around the stone (especially star patterns). This type of setting was developed in the late 1800's and was often used for rings. The gypsy setting is also known as the "star setting."
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Girdle | The widest part of most diamonds, the middle between the crown and pavilion. May be rough (matt), polished or facetted. Even if facetted, it is only counted as one facet.
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Girdle Facet | Any of the facets adjacent to the girdle on a brilliant cut or other diamond, split into upper (crown) girdle facets, and lower (pavilion) girdle facets.
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Gletz | Dutch or Afrikaans for feather. Also spelt glatts, glatze, gles, and glets.
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Global Witness | An organisation set up in 1993 by three individuals to counter conflict and corruption in countries often rich in resources, and promote the welfare of the resident population.
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Global Witness Reports | Various reports by Global Witness into a number of unsavoury aspects of the exploration extraction and exploitation section of the diamond industry, leading to the Kimberley Process.
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Gold | Yellow precious metal used in most jewellery in various alloys.
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Golden Jubilee | The largest faceted diamond in the world, weighing 545.67 carats.
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Goods | An expression sometimes used by diamond dealers meaning "diamonds".
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Grade | A recognised measure of an aspect of quality, mainly clarity and colour, but can also be applied to proportion and other aspects.
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Grading | The process of appraising a diamond, and allocating grades to it.
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Grain | Diamond crystal have different strength bonds in different directions. These directions are known as grain rather like the grain in wood. Also an obsolescent unit of weight, equal to a quarter carat or 0.042 pennyweight, 0.002083 troy ounce, 0.0648 grams.
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Grainer | A quarter carat (approximately) diamond. A two-grainer would weight about a half carat, a three-grainer about 0.75 carats, and a four-grainer about one carat, etc.
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Graining | Internal Graining refers to internal irregular crystal growth. May appear milky, like faint lines or streaks, colored or reflective.
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Grease | Diamonds have an affinity for grease and oil. They act as "grease magnets". Grease and oil on the surface of diamonds reduces their effective RI and therefore their brilliance.
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Grease Tables | Because diamonds stick to grease, grease table are used in diamond mines, and have been since 1896, to help separate diamonds from crushed rock.
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Great Chrysanthemum | A 198.28-carat fancy brown pear shaped diamond.
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Green | A rare colour of diamond.
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Grit | Small pieces of rough diamond, used as industrial abrasives, may be natural or synthetic.
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Guinea | This west African country is currently about the world's tenth largest diamond producer by value.
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Gyémánt | Gyémánt is the Hungarian word for diamond.
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There are currently over 600 entries in this table.
Over 90 of them have page links to a page on this site. Eventually, we intend to add a more complete description for most entries, each on its own page.
Please watch this space!