The Red Cross Diamond is a canary-yellow 205.07-carat, cushion-shaped cut diamond which is among the largest known cut diamonds. The diamond was auctioned off in 1918 to support the British Red Cross Society. It has a Maltese cross visible in the diamond.
The diamond is referred to as the Red Cross Diamond and it is classified as "fancy intense yellow" in color. It is commonly referred to as canary-yellow.It has a cushion shaped cut and a Maltese cross faceted at its base. The Maltese cross feature in the diamond was considered a rarity and in 1918 only two other diamonds were known to have the feature: the Regent Diamond being one. The diamond is 205.07 carats (41.014 grams) and it is a brilliant cut diamond with "nearly flawless VS2 clarity". It is considered to be one of the world’s largest diamonds. In 1918 it was called the largest yellow diamond in the world.
In 1901 the diamond was found in the De Beers controlled Kimberley Mine at Griqualand West, Cape Colony (in modern South Africa).The rough diamond is said to have weighed between 370 and 380 carats. It was bought by "The Diamond Syndicate" and when it reappeared in 1918, it was a cut diamond. The stone was cut in Amsterdam. It was sent to Christie's as a donation, to be auctioned to benefit the Red Cross. It came to be known as the Red Cross diamond after it contributed to the fund of the British Red Cross Society. The diamond was displayed prior to the auction and people could view it after paying a fee. Prior to the 1918 auction the News-Democrat, an American newspaper, stated, "If it brings less than a million dollars, it will be a bargain, as diamonds go."
At the auction the diamond was purchased by the London firm S. J. Phillips for £10,000and the proceeds went to fund the British Red Cross Society during World War I.
The owner of the diamond attempted to resell it at auction in Tokyo in July 1973. Pre-auction estimates anticipated a US$5 million sale. Twenty buyers attended the auction and a bid of 570 million yen was rejected.The diamond was then auctioned by Christie's (Geneva) in November 1973 and it sold to an American businessman for 1.8 million Swiss francs.
On May 11, 2022, the Red Cross Diamond was purchased for 14.2 million Swiss francs at Christie's Geneva. This was the third time Christie's auctioned the diamond.The consigner of the diamond stated that part of the proceeds from the auction would be donated to the International Red Cross Movement.
The Deepdene is a 104.52 carats (20.904 g) yellow diamond widely considered to be the largest irradiated diamond in the world.
The Allnatt Diamond is a diamond measuring 101.29 carats with a cushion cut, rated in color as Fancy Vivid Yellow by the Gemological Institute of America. This diamond was named after one of its holders, Major Alfred Ernest Allnatt, a soldier, sportsman, art patron and benefactor.
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The Premier Mine is an underground diamond mine owned by Petra Diamonds in the town of Cullinan, 40 kilometres (25 mi) east of Pretoria, Gauteng Province, South Africa. Established in 1902, it was renamed the Cullinan Diamond Mine in November 2003 in celebration of its centenary. The mine rose to prominence in 1905, when the Cullinan Diamond – the largest rough diamond of gem quality ever found – was discovered there. The mine has produced over 750 stones that are greater than 100 carats (20 g) and more than a quarter of all the world's diamonds that are greater than 400 carats (80 g). It is also the only significant source of blue diamonds in the world.
Harry Winston was an American jeweler. He donated the Hope Diamond to the Smithsonian Institution in 1958 after owning it for a decade. He also traded the Portuguese Diamond to the Smithsonian in 1963 in exchange for 3,800 carats of small diamonds.
De Grisogono was a Swiss luxury jeweller. It was founded in Geneva, Switzerland, in 1993 by Lebanese-Italian black diamond specialist Fawaz Gruosi The Italian name Grisogono is derived from the Latin Chrysogonus which comes from the Greek Chrysogonos χρῡσό-γονος, meaning "begotten of gold". De Grisogono filed for bankruptcy on 29 January 2020.
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Graff is a British multinational jeweller based in London. It was founded by British jeweller Laurence Graff in 1960. A vertically integrated company, Graff operations comprise the design, manufacture and retail distribution of jewellery and watches.
The Patiala Necklace was a necklace designed & made by the Cartier S.A. in 1928. It was made for Bhupinder Singh of Patiala, who was the Maharaja of the princely state of Patiala.
The Archduke Joseph is a colorless, antique cushion-shaped brilliant, originally weighing 78.54 carat, purchased by Molina Jewelers of Arizona sometime in the late-1990s and slightly re-cut to 76.45 carat to improve clarity and symmetry. It is, on the Gemological Institute of America (GIA) color and clarity scales, a D grade, IF diamond and the largest DIF ever graded at the GIA; and it is of type IIa.
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Lesedi La Rona, formerly known in media as Karowe AK6 or as Quad 1 by the personnel at the mine, is the fourth-largest diamond ever found, and the third-largest of gem quality. It was found in the Karowe mine, in Botswana on 16 November 2015.
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The Polar Star diamond is a 41.28 carat brilliant cushion-cut diamond, from the Golconda region in India. Its lower pavilion is arranged as an eight-pointed star, hence its name, from Polaris, the Northern Star. It is claimed that "the symmetry of the cut is so precise that it can be balanced on its culet" It is a rare type IIa diamond, meaning that it contains no nitrogen or boron. It is likely D or E color ("colourless"), with a trace of pink, and has blue fluorescence.
The Queen Marie of Romania Sapphire is a 478.68 carat Cornflower blue cushion cut Ceylon sapphire. When it was sold at Christie's in 2003, it was the largest sapphire ever offered at auction. It is named for its association with its first owner, Marie of Edinburgh, Queen of Romania.
The Rock is the world's largest white diamond ever auctioned. It is a nearly colorless 228.31 carat pear-shaped diamond mined in South Africa c. 2000. The diamond is described as larger than a golf ball, and it was auctioned in 2022 for 21.9 million USD.