List of Diamond

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.

• The 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, an antique round cut weighing 38 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 Raj, and is now part of the Crown of Queen Elizabeth the Queen Mother.
• The Lesotho
• 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.
• 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 South Africa, also known as the Dudley Diamond. 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 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, 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.

Sinthetics, simulants and enhancements of diamond

Synthetics

Synthetic diamonds are diamond crystals that are manufactured in a laboratory, as opposed to natural diamonds which form naturally within the earth.

The gemological and industrial uses of diamond have created a large demand for rough stones. This demand has long been satisfied in large part by synthetic diamonds, which have been manufactured by various processes for more than half a century. However, in recent years it has become possible to produce gem-quality synthetic diamonds of significant size.^[41]

The majority of commercially available synthetic diamonds are yellow in color and produced by so called High Pressure High Temperature (HPHT) processes.^[42] The yellow color is caused by nitrogen impurities. Other colors may also be reproduced such as blue, green or pink which are a result of the addition of boron or from irradiation after synthesis.^[43]

At present, the annual production of gem quality synthetic diamonds is only a few thousand carats, whereas the total production of natural diamonds is around 120 million carats. Despite this fact, a purchaser is more likely to encounter a synthetic when looking for a fancy-colored diamond because nearly all synthetic diamonds are fancy-colored, while only 0.01% of natural diamonds are fancy-colored.^[44]

Producing large synthetic diamonds threatens the business model of the diamond industry. The ultimate effect of the ready availability of gem-quality diamonds at low cost in the future is hard to predict.

Simulants

A diamond simulant is defined as a non-diamond material that is used to simulate the appearance of a diamond. Diamond-simulant gems are often referred to as diamante.

The most familiar diamond simulant to most consumers is cubic zirconia (commonly abbreviated as CZ). The popular gemstone moissanite is often mischaracterized as a diamond simulant, although it is marketed as a gemstone in its own right rather than explicitly as a diamond simulant. While moissanite does look similar to diamond, its main disadvantage as a diamond simulant is that CZ is far cheaper and arguably equally convincing. Both CZ and moissanite are synthetically produced.

Enhancements

Diamond enhancements are specific treatments performed on natural or synthetic diamonds (usually those already cut and polished into a gem), which are designed to better the gemological characteristics of the stone in one or more ways. These include laser drilling to remove inclusions, application of sealants to fill cracks, treatments to improve a white diamond's color grade, and treatments to give fancy color to a white diamond.

Coatings are increasingly used to give a diamond simulant such as cubic zirconia a more "diamond-like" appearance. One such substance, which is heavily advertised, is what scientists refer to as "diamond-like carbon". This is an amorphous carbonaceous material that has some physical properties which are similar to that of the diamond. Advertising suggests that such a coating would transfer some of these diamond-like properties to the coated stone, hence enhancing the diamond simulant. However, modern techniques such as Raman Spectroscopy should easily identify such as treatment.^[45]

Identification

In the 22 November 2008 issue of New Scientist, it was stated that Russell Hemley of the Geophysical Laboratory at the Carnegie Institution for Science had discovered a technique to make diamonds via microwaves which were indistiguishable from natural diamonds. Yufei Meng, a scientist from the same laboratory, claimed that after having sent these diamonds for diamond jewellery identification, they were not identified as different from natural diamonds.^{[citation needed]} Such claims are often made for new synthetics, simulants, and treated stones, so it is important to validate how the stones were submitted for identification. For example, the "test" could simply refer to showing the stones to an unqualified jewellery shop assistant.

Properly-trained and equipped gemologists can distinguish between natural diamonds and synthetic diamonds. They can also identify the vast majority of treated natural diamonds, two exceptions being a small minority of HPHT-treated Type II diamonds and some artificially-irradiated green diamonds. "Perfect" crystals (at the atomic lattice level) have never been found to exist anywhere, so both natural and synthetic diamonds always possess characteristic imperfections, arising from the circumstances of their crystal growth, that allow them to be distinguished from each other.

Laboratories use techniques such as spectroscopy, microscopy and luminescence under shortwave ultraviolet light to determine a diamond's origin. They also use specially-made machines to aid them in the identification process. Two screening machines are the DiamondSure and the DiamondView, both produced by the DTC and marketed by the GIA.^[46]

Several methods for identifying synthetic diamonds can be performed, depending on the method of production and the color of the diamond. CVD diamonds can usually be identified by an orange fluorescence. D-J colored diamonds can be screened through the Swiss Gemological Organization's^[47] Diamond Spotter. Stones in the D-Z color range can be examined through the DiamondSure UV/visible spectrometer which is a tool developed by De Beers.^[48] Similarly, natural diamonds usually have minor imperfections and flaws, such as inclusions of foreign material, that are not seen in synthetic diamonds.