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Brakfontein PDF Print E-mail
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Friday, 14 September 2007
Brakfontein. A minor alluvial dia¬mond deposit in the Hopetown area, Cape Province, Republic of South africa. The yearly yield from this deposit is inconsequential.
 
Braganza Diamond PDF Print E-mail
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Thursday, 13 September 2007
Braganza diamond. When Brazil was a part of Portugal, a 1680-carat stone reported to be a diamond was found in that South American coun-Iry. However, it is generally thought to be a topaz, not a diamond. It has been reported to belong to the Por¬tuguese Government, but officials of that country, in a communication to the Gemological Institute of America, refute this belief.
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Brady Diamond PDF Print E-mail
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Thursday, 13 September 2007
Brady diamond. Discovered in 1902 on the Vaal River, Cape Province, Republic of South africa. The rough weighed 330 carats. Present where¬abouts unknown.
 
bow tie PDF Print E-mail
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Thursday, 13 September 2007
bow tie. A darkened area across the center of a fancy cut stone exhibiting a "bow tie" appearance when view¬ed through the table. Seen in ovals, Oval Pear shape Marquise Bow tie pears, heart shape, and marquises. Also known as the bow tie effect.
 
bourse PDF Print E-mail
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Thursday, 13 September 2007
bourse. French, meaning an ex¬change or meeting place where mer¬chants transact business. The word is often used for a diamond dealers' club or similar jewelry-trade associa¬tion. See DIAMOND BOURSE, DIAMOND CLUB.
 
Botswana PDF Print E-mail
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Thursday, 13 September 2007
Botswana, Republic of. Formerly called Bechuanaland up to 1966. It lies between Rhodesia, Republic of South africa, and South-West Africa. It is the site of the Orapa pipe mine, designated 2125 A/K1, and 16 other kimberlite pipes. diamond produc¬tion in 1 975 reported to be 2,052,000 carats industrial and 365,000 carats gem quality.
 
bort PDF Print E-mail
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Thursday, 13 September 2007
bort (also boart, boort, bortz, bowr). The lowest quality of diamond, so badly flawed and imperfectly crystal¬lized that it is suitable only for crush¬ing into abrasive powders for a mul¬titude of industrial purposes. Kasai Province, in the Republic of Zaire, is by far the world's greatest producer of this material. See STEWARTITE, HAIL¬stone BORT, FRAMESITE BORT, SHOT BORT.
 
boron PDF Print E-mail
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Thursday, 13 September 2007
boron. Element of atomic number 5 found in nature only in combination; symbol B, atomic weight 10.81, va¬lence 3, used in metallurgy and nu¬cleonics. One of the many impurities in diamond which is now believed to cause the semi-conductor properties and the blue color in Type lib dia¬monds instead of aluminum.
 
Bornholm diamond PDF Print E-mail
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Thursday, 13 September 2007
Bornholm diamond. A misnomer for rock crystal from marl concretions at Laessa and Olenaa, Denmark.
 
boort PDF Print E-mail
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Thursday, 13 September 2007
boort. An alternate spelling of bort. Borazon (trademark). A man-made cubic form of boron nitride produced under high pressures (45-75 kilobars) and high temperatures (1200-2000° C). Its hardness, specific gravity and atomic structure are comparable to diamond. Borazon, a non-gem, was first synthesized by the General Elec¬tric Company in 1957. It may be black, brown, dark red, white, gray or yellow in color and is far more heat resistant than diamond. Cubic boron nitride may also be made into strong polycrystalline masses by binding small crystals together under controlled temperature and pressure to form "compacts" of usable size for cutting tools.
 
Booi PDF Print E-mail
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Thursday, 13 September 2007
Booi. A young Griqua shepherd who discovered an 83V2-carat crystal on the Zandfontein Farm in March, 1869, which started the world-wide rush of fortune seekers to South Af¬rica. The stone later became known as the Star of South africa.
 
Bombay PDF Print E-mail
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Thursday, 13 September 2007
Bombay. Major diamond cutting and marketing center of India. The towns of Surat and Navsari located north of Bombay also have cottage industry cutters.
 
bombarded diamond PDF Print E-mail
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Thursday, 13 September 2007
bombarded diamond. A diamond that has been subjected to bom¬bardment by fast electrons, neutrons, deuterons, etc. The purpose of bom¬bardment is to make the color of the stone more attractive and desirable. See CYCLOTRON-TREATED DIAMOND, ELEC¬TRON-BOMBARDED DIAMOND, PILE-TREATED DIA¬MOND.
 
Boismenu PDF Print E-mail
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Thursday, 13 September 2007
Boismenu, F. A French scientist who, in 1908, claimed to have made di¬amonds with great heat and little pressure. His system was to heat cal¬cium carbide in a carbon arc. He thought he had obtained, through electrolysis, minute diamond crystals on the carbon cathode. There is no proof that his experiments were suc¬cessful. See SYNTHETIC DIAMOND. bomba. Venezuelan term for diamond diggers who move from one place to another in a series of diamond "rushes."
 
body color PDF Print E-mail
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Thursday, 13 September 2007
body color. The color of a diamond as observed when examined under diffused light against a hueless background free from surrounding reflections. The diffused light elimi- nates glaring reflections and disper¬sion, which would otherwise confuse the color determination. See COLOR GRADE, DIAMONDLITE, MASTER (OR KEY) Diamonds, FACE-UP COLOR, NORTH DAYLIGHT. Bogenfels. A region lying north of I he Orange River mouth and south of l.uderitz, along the coast of South¬west africa, from which important diamond production was taken. Much of the area has been mined OUt. See SOUTH-WEST AFRICA. Bohemia. In 1869, several isolated diamond finds were made in the garnet-bearing sands of Bohemia, but the discoveries were of scientific in¬terest only.
 
Bob Grove Diamond PDF Print E-mail
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Thursday, 13 September 2007
Bob Grove diamond. A 337-carat crystal. Found in 1908 on the Vaal River, Cape Province, Republic of South africa. Additional information unavailable.
 
Bob Craig Diamond PDF Print E-mail
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Thursday, 13 September 2007
Bob Craig diamond. Found in 1917, on the Vaal River, Cape Province, Republic of South africa. 100 carats. Disposition unknown.
 
Boa Vista Mine PDF Print E-mail
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Thursday, 13 September 2007
Boa Vista Mine. An important diamond mine in the Diamantina re¬gion, Minas Gerais, Brazil.
 
boart PDF Print E-mail
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Thursday, 13 September 2007
boart. An alternate spelling of bort. boat-shaped rose cut. A rarely used rose style of cutting. It has an ellipti¬cal (boat-shaped) girdle outline, a flat, unfaceted base and a pointed, dome-shaped crown bearing 24 triangular facets; the number of facets, however, may vary.
 
blue-white Wesselton. PDF Print E-mail
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Thursday, 13 September 2007
"blue-white Wesselton." A confus¬ing and misleading term for top Wes-selton, since this grade falls just below the finest classification on the river-to-light-yellow diamond color-grading system; hence, stones in this classification do not have a blue tint. See TOP WESSELTON, BLUE-WHITE.
 
blue-white PDF Print E-mail
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Thursday, 13 September 2007
"blue-white." A term that has been used for many years to refer to a diamond without body color. How¬ever, it is applied frequently, but incorrectly, to stones that have a distinct yellow tint. Federal Trade Commission rulings state that it is an unfair trade practice to apply the term to any stone having a body color other than blue or bluish. A similar American Gem Society ruling prohibits the use of the term by its members. Flagrant misuse has made the term meaningless.
 
blue Wesselton PDF Print E-mail
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Thursday, 13 September 2007
"blue Wesselton." A confusing and misleading term for top Wesselton, since this grade falls just below the finest classification on the river-to-light-yellow diamond color-grading system; hence, stones in this classifi¬cation do not have a blue tint. See TOP WESSELTON.
 
blue river PDF Print E-mail
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Thursday, 13 September 2007
"blue river." A confusing and mis¬leading term, since the diamond color grade known as river refers only to an extraordinarily transpa¬rent, colorless stone. See RIVER.
 
blue jager PDF Print E-mail
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Thursday, 13 September 2007
"blue jager" (yah"-ger). Jager is the color grade for Diamonds that have a faint blue body color in daylight. On the apparent assumption that this is not universally known to jewelers, some importers refer to such stones as "blue jagers," an obvious redun¬dancy. They were originally de¬scribed from the Jagersfontein Mine. See JAGER.
 
Blue Heart Diamond PDF Print E-mail
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Thursday, 13 September 2007
Blue Heart diamond. A 31-carat deep-blue heart-shaped diamond ini¬tially sold by Cartier, in 1911, to the Parry family of Buenos Aires, Argen¬tina. In 1953, the Blue Heart reap¬peared when Van Cleef exhibited the stone as a necklace pendant valued at $300,000. It was reportedly sold by Van Cleef's Paris office in 1953 but returned for resale to an undis¬closed buyer in 1960. Blue Jacket. One of the early alluvial diamond diggings on the Vaal River, Republic of South africa.
 
Blue Diamond PDF Print E-mail
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Thursday, 13 September 2007
Blue diamond of the Crown Diamond. See FRENCH BLUE DIAMOND. blue earth. Same as blue ground. blue ground. A miner's name for kim-berlite, the rock that containsdiamonds in the South African pipe mines. See KIMBERLITE, YELLOW GROUND, HARDEBANK.
 
blue diamond PDF Print E-mail
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Thursday, 13 September 2007
blue diamond. A diamond with a dis¬tinctly blue body color, even though very light in tone, is a fancy diamond. Diamonds that are blue in both daylight and incandescent light are rare, although fluorescent stones that show a blue color in daylight are comparatively common. A blue body color may also be induced artifi¬cially. See BRUNSWICK BLUE DIAMOND, ELECTRON-BOMBARDED DIAMOND, FANCY DIAMOND, FLUORESCENCE, FRENCH BLUE DIAMOND, HOPE DIAMOND, JACER, PREMIER DIAMOND, ROBERTS-VICTOR, TAVERNIER BLUE DIAMOND, WITTELSBACH DIAMOND.
 
Blue Brilliant Diamond PDF Print E-mail
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Thursday, 13 September 2007
Blue Brilliant diamond. A 1.25-carat blue diamond, reported by Streeter (1882) in his discussion of the French Blue and Hope Diamond, which he bought from Messrs. Hertz & Co., Paris, for £ 300. Streeter believed it to be a fragment from the recutting of the French Blue because "Its colour is identical with that of the Hope . . ."; however, Tillander's 1975 study negates this assumption. This blue diamond may be the Pirie Diamond, bought in Paris in 1877 by Edwin W. Streeter, but its weight is reported to be only one carat. See PIRIE DIAMOND.
 
blocker PDF Print E-mail
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Thursday, 13 September 2007
blocker. A diamond cutter who specializes in placing the first 18 (main) facets on a brilliant-cut diamond (17, if there is no culet). On the crown he places the table and eight bezel facets (or the four bezel and four top-corner facets); on the pavilion he places the culet (if any) and the eight pavilion facets (of the four pavilion and four bottom-corner facets). With four facets above and four below, the stone is called a four-square or a cross; with eight crown and eight pavilion facets, the lorm eight-square is applied. Also known as tapper, or cross-cutter. blocking. The process of placing the first 18 (main) facets on a diamond brilliant (17, if there is no culet). Also known as lapping.
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blemish PDF Print E-mail
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Thursday, 13 September 2007
blemish. A term used to refer to a surface imperfection on a fashioned diamond; e.g. a nick, knot, scratch, abrasion, minor crack or cavity, or poor polish. Also, a natural on the girdle or an extra facet is usually considered a blemish. See FLAW, IMPER¬FECTION.
 
blade diamond dressing tool PDF Print E-mail
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Thursday, 13 September 2007
blade diamond dressing tool. A multiple-diamond dressing tool that contains one or more layers of Diamonds set in single rows of two or more.
 
Black Star of Africa Diamond PDF Print E-mail
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Thursday, 13 September 2007
Black Star of africa diamond. This 202-carat stone is reported to be the largest colored-diamond in the world. It was in a special exhibit of Belgian gems at Tokyo in 1971 where it was valued at $1.2 million.
 
Black Orloff PDF Print E-mail
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Thursday, 13 September 2007
Black Orloff (or Eye of Brahma) diamond. According to legend, the Black Orloff is said to have taken its name from the Russian Princess Nadia Vyegin-Orloff, who owned it for a time during the mid-eighteenth century. It is a 67.50-carat cushion-cut stone, a so-called black diamond (actually, a very dark gun-metal color). The Black Orloff is also re¬ported to have once belonged to a nineteenth-century shrine near Pon-dicherry, India, and to have weighed 195 carats in the rough. The stone has been exhibited widely, including the American Museum of Natural History in 1951, the Wonderful World of Fine Jewelry & Gifts at the 1964 Texas State Fair, Dallas, and the Diamond Pavilion in Johannesburg in 1967. The Black Orloff is owned by Charles F. Winson, New York City gem dealer, who values it at $150,000. It is mounted in a modern diamond-and-platinum necklace.
 
Black Diamond of Bahia PDF Print E-mail
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Thursday, 13 September 2007
Black diamond of Bahia. Discovered in Bahia, Brazil; date unknown. 350-carat black crystal. Shown at 1851 Crystal Palace Exposition in London, where it was described as "so hard it can't be polished." Whereabouts unknown. blackened culet. Culets in some early diamond jewelry had a spot of black paint or pitch applied which appeared as a black spot through the table.
 
black diamond PDF Print E-mail
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Thursday, 13 September 2007
black diamond. (1) When a diamond is dark gray, a very dark hue, or truly black, it is referred to in the trade as a black diamond. Such a stone may be opaque to nearly semitransparent. (2) Carbonado, a particularly tough industrial variety of diamond. (3) A misnomer for hematite or anthracite coal.
 
bizel PDF Print E-mail
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Thursday, 13 September 2007
bizel. Same as bezel. Blaauwboschkuil. A minor alluvial diamond deposit in the Wol-maransstad area, Transvaal Province, Republic of South africa. A produc¬tion of only about 100 carats was re¬ported for one recent year.
 
Birmingham Diamond PDF Print E-mail
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Thursday, 13 September 2007
Birmingham diamond. Found in 1900 near Birmingham, Shelby Co., Alabama. Unofficial name. Slightly yellow 4.25-carat octahedron. Own¬ed by American Museum of Natural History, New York City.
 
birefringence PDF Print E-mail
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Thursday, 13 September 2007
birefringence. The measure of dou¬ble refraction of crystals other than those of the isometric system (singly refractive), the amount being mea¬sured by the difference between the greatest and least refractive indices. diamond is considered usually opti¬cally isotropic (singly refractive) and has anomalous birefringence caused by strain due to inclusions and/or the presence of two types of materials, Type I and Type II diamond.
 
Big Hole PDF Print E-mail
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Thursday, 13 September 2007
Big Hole. The latest name for the Kimberley Mine. Originally called the "Colesberg Kopje," "De Beers New Rush," and afterwards the "Kimberley Mine." The Kimberley Mine was abandoned in 1914, after yielding 25,000,000 tons of kimberlite containing about three (3) tons of Diamonds. See NEW RUSH, KIMBERLEY MINE.
 
Big Five PDF Print E-mail
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Thursday, 13 September 2007
Big Five. The Bultfontein, De Beers, Dutoitspan, Kimberley and Wessel-ton diamond pipe mines. See KIMBER¬LEY MINES.
 
bicycle tire PDF Print E-mail
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Thursday, 13 September 2007
"bicycle tire." A slang term for a gir¬dle on a round, brilliant-cut diamond that is so thick as to be very notice¬able to the unaided eye. See GIRDLE, GIRDLE THICKNESS.
 
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