Diamonds: February 2009

Friday, February 27, 2009

List of diamonds
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A number of large or extraordinary diamonds have gained fame, both as exquisite examples of the beautiful nature of diamonds, and because of the famous people who wore, bought, and sold them. These diamonds are often depicted in marketing materials aimed at the retail diamond customer. A partial list of famous diamonds in history follows.

Darya-ye Noor
Tiffany Yellow DiamondThe Allnatt Diamond, a large antique cushion-shaped brilliant Fancy Vivid Yellow diamond.
The Agra Diamond, antique cushion-shaped stellar brilliant, 28 carats.
The Amsterdam Diamond, a 33.74 carat (6.748 g) pear-shaped black diamond which sold for $352,000 in 2001.
The Archduke Joseph Diamond, antique cushion-shaped brilliant, 76 carats.
The Ashberg Diamond
The Aurora Butterfly of Peace
The Aurora Pyramid of Hope
The Beau Sancy, a 34-carat diamond not to be confused with the Sancy.
The Black Orlov, a 67.50 carat cushion-cut black diamond, also called the Eye of Brahma Diamond.
The Blue Heart Diamond, 30.82-carat heart brilliant. Part of the Smithsonian collection.
The Briolette of India Diamond, 90 carats.
The Centenary Diamond, modified heart-shaped brilliant, the world's largest colorless (grade D), flawless diamond.
The Chloe Diamond, largest round brilliant-cut diamond ever put on auction. Sold on November 14th, 2007 at Sotheby's in Geneva to Georges Marciano of the Guess clothing line for $16.2 million, the second-highest price ever paid for a diamond on auction. Took 2 years to cut.
The Cullinan Diamond, the largest rough gem-quality diamond ever found at 3106.75 carats (621.35 g). It was cut into 105 diamonds including the Cullinan I or the Great Star of Africa, 530.2 carats (106.04 g), and the Cullinan II or the Lesser Star of Africa, 317.4 carats (63.48 g), both of which are now part of the British Crown Jewels.
The Darya-ye Noor Diamond, the largest pink diamond in the world, about 186 carats (36.4 g), part of Iranian Crown Jewels. Its exact weight isn't known and 186 carats is an estimate.
The Deepdene, widely considered to be the largest artificially irradiated diamond in the world.
The De Young Red Diamond, the third-largest known red diamond was bought in a flea market on a hatpin by Sidney deYoung a prominent Boston estate jewelry merchant. It was donated by him to the museum of natural history.
The Dresden Green Diamond, antique pear-shaped brilliant - its color is the result of natural irradiation
The Dresden White Diamond, 47-carat antique oval brilliant, colorless/near-colorless
The Dresden Yellow Diamond
The Dudley Diamond also known as the Star of South Africa. This must not be confused with the Star of Africa. The Star of South Africa was the initial name given to this diamond, when it was purchased as an 83.5-carat rough diamond. The diamond is a D-color, pear-shaped stellar brilliant cut stone, weighing 47.69 carats.
The Earth Star Diamond a 111.59-carat, pear-shaped diamond with a strong coffee-like brown color.
The Empress Eugenie Diamond, 52-carat antique pear-shaped brilliant with an odd, random facet pattern
The Excelsior Diamond, the largest known diamond in the world prior to the Cullinan
The Florentine Diamond, a lost diamond, light yellow with a weight of 137.27 carats (27.45 g).
The Golden Jubilee Diamond, the largest faceted diamond ever cut at 545.67 carats (109.13 g)
The Graff Blue Diamond
The Great Chrysanthemum Diamond
The Great Mogul Diamond, fabled 280-carat mogul-cut diamond, now lost, although presumed by historians to have been recut as the Orlov.
The Gruosi Diamond, a heart-shaped black diamond, weighing 115.34 carats.
The Heart of Eternity Diamond, perhaps the largest Fancy Vivid Blue
The Hope Diamond, Fancy Dark Grayish-Blue and supposedly cursed. Almost certainly cut from the French Blue Diamond
The Hortensia Diamond, peach color, formerly part of the French Crown Jewels. Displayed in the Louvre.
The Idol's Eye
The Incomparable Diamond, a brownish-yellow diamond of 407.48 carats (81.496 g) cut from an 890 carat (178 g) rough diamond of the same name - it appeared on eBay in 2002. Internally Flawless clarity.
The Jacob Diamond weighing 184.5 carats (36.90 g), also known as Imperial Diamond & Victoria Diamond.
The Jones Diamond
The Jubilee Diamond, originally known as the Reitz Diamond; perhaps the sixth-largest in the world.
The Kimberley Diamond
The Koh-i-Noor, a 105 carat (21.6 g) white of Indian origin, with a long and turbulent history and a good deal of legend surrounding it. After belonging to various Mughal and Persian rulers, it was taken away from the Maharaja Duleep Singh of Lahore and was presented to Queen Victoria during the British occupation of India, and is now part of the Crown of Queen Elizabeth the Queen Mother.
The Lesotho Promise, is the 15th-largest diamond, the tenth-largest white diamond, and the largest diamond to be found in 13 years
The Millennium Star, at 203 carats is the second-largest colorless (grade D), flawless diamond.
File:Pumpkindiamond4.jpg
Pumpkin Diamond
Koh-i-Noor (glass replica)The Moon of Baroda
The Moussaieff Red Diamond, the largest known Fancy Red
The Mouna Diamond, 112 carats, Fancy Intense Yellow cushion-shaped brilliant.
The Nassak Diamond[1]
The Nepal Diamond, fine quality antique pear-shaped brilliant, sold by Harry Winston to private collector in 1961. Thought to have originated from the Golconda Mines.
The Nizam Diamond
The Nur-Ul-Ain Diamond
The Ocean Dream Diamond, the only known natural Fancy Deep Blue-Green.
The Oppenheimer Diamond, one of the largest gem-quality uncut diamonds in the world.
The Orlov, an Indian mogul cut rumored to have served as the eye of a Hindu statue.
The Paragon Diamond
The Porter Rhodes Diamond, a colorless 53-carat Asscher-cut stone.
The Portuguese Diamond, 127-carat antique emerald cut with a pale yellow body color and very strong blue fluorescence. Part of the Smithsonian's collection.
The Premier Rose Diamond, 137.02-carat (27.4 g) stone cut from a 353.9-carat (70.8 g) rough gem of the same name
The Pumpkin Diamond, perhaps the largest Fancy Vivid Orange. 5.54 carats, modified cushion-shaped brilliant.
The Red Cross Diamond, 205 carats, yellow, cushion-shaped stellar brilliant cut.
The Regent Diamond, cushion-shaped stellar brilliant cut, formerly belonging to Louis XV, Louis XVI, and Napoleon Bonaparte, it now resides in the Louvre.
The Sancy, a shield-shaped pale yellow diamond currently in the Louvre.
The Shah Diamond, very old yellow diamond (found approximately in 1450 in India) currently housed in the Diamond Fund in Kremlin
The Spirit of de Grisogono Diamond, 312 carats, the world's largest cut black diamond.
The Spoonmaker's Diamond, circa 86-carat (17 g) diamond housed in Topkapı Palace in Istanbul.
The Star of Arkansas
The Star of the East, a 95-carat (19 g) stone once owned by Mrs. Evalyn McLean of Washington DC, who also owned the Hope Diamond.
The Star of the South
The Steinmetz Pink Diamond, modified oval brilliant cut (step cut crown, brilliant pavilion), largest known Fancy Vivid Pink.
The Taylor-Burton Diamond
The Tereschenko Diamond, 42-carat antique pear brilliant cut.
The Tiffany Yellow Diamond, antique modified cushion-shaped stellar brilliant cut, on display at Tiffany & Co.'s New York City store.
The Uncle Sam Diamond, the largest discovered in the US, emerald-cut, M color (pale brown), VVS2 clarity.
The Vargas
The Wittelsbach Diamond, 35.52 carats, Fancy Deep Grayish Blue, antique oval stellar brilliant cut. Sold at Christie's, London, December 10, 2008 for $23.4 million, currently the highest price ever paid for a diamond at auction.

Diamond Formation

Formation
The formation of natural diamond requires very specific conditions. Diamond formation requires exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60 kilobars,[18] but at a comparatively low temperature range between approximately 1652–2372 °F (900–1300 °C).[18] These conditions are known to be met in two places on Earth; in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike.

Diamonds formed in cratons
The conditions for diamond formation to happen in the lithospheric mantle occur at considerable depth corresponding to the aforementioned requirements of temperature and pressure. These depths are estimated to be in between 140–190 kilometers (90–120 miles)[18][10] though occasionally diamonds have crystallized at depths of 300-400 km (180-250 miles) as well.[19] The rate at which temperature changes with increasing depth into the Earth varies greatly in different parts of the Earth. In particular, under oceanic plates the temperature rises more quickly with depth, beyond the range required for diamond formation at the depth required.[18] The correct combination of temperature and pressure is only found in the thick, ancient, and stable parts of continental plates where regions of lithosphere known as cratons exist.[18] Long residence in the cratonic lithosphere allows diamond crystals to grow larger.

The slightly misshapen octahedral shape of this rough diamond crystal in matrix is typical of the mineral. Its lustrous faces also indicate that this crystal is from a primary deposit.Through studies of carbon isotope ratios (similar to the methodology used in carbon dating, except with the stable isotopes C-12 and C-13), it has been shown that the carbon found in diamonds comes from both inorganic and organic sources. Some diamonds, known as harzburgitic, are formed from inorganic carbon originally found deep in the Earth's mantle. In contrast, eclogitic diamonds contain organic carbon from organic detritus that has been pushed down from the surface of the Earth's crust through subduction (see plate tectonics) before transforming into diamond.[10] These two different source carbons have measurably different 13C:12C ratios. Diamonds that have come to the Earth's surface are generally quite old, ranging from under 1 billion to 3.3 billion years old. This is 22% to 73% of the age of the Earth.

Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles or maccles. As diamond's crystal structure has a cubic arrangement of the atoms, they have many facets that belong to a cube, octahedron, rhombicosidodecahedron, tetrakis hexahedron or disdyakis dodecahedron. The crystals can have rounded off and unexpressive edges and can be elongated. Sometimes they are found grown together or form double "twinned" crystals at the surfaces of the octahedron. These different shapes and habits of the diamonds result from differing external circumstances. Diamonds (especially those with rounded crystal faces) are commonly found coated in nyf, an opaque gum-like skin.[20]

Diamond History

Thursday, February 26, 2009

Diamond

di·a·mond (d-mnd, dmnd)
n.
1. An extremely hard, highly refractive crystalline form of carbon that is usually colorless and is used as a gemstone and in abrasives, cutting tools, and other applications.
2. A piece of jewelry containing such a gemstone.
3. A figure with four equal sides forming two inner obtuse angles and two inner acute angles; a rhombus or lozenge.
4. Games
a. A red, lozenge-shaped figure on certain playing cards.
b. A playing card with this figure.
c. diamonds (used with a sing. or pl. verb) The suit of cards represented by this figure.
5. Baseball
a. An infield.
b. The whole playing field.
adj.
Of or relating to a 60th or 75th anniversary.
tr.v. di·a·mond·ed, di·a·mond·ing, di·a·monds
To adorn with or as if with diamonds.
Idiom:
diamond in the rough
One having exceptionally good qualities or the potential for greatness but lacking polish and refinement.