The 14.62-carat ‘Oppenheimer Blue’ sold for a record $57.5 million on May 18, 2016. $ 3.93m per carat.
|All coloured diamonds contain interstitial impurities or structural defects that cause the colouration. Pure diamonds are transparent and colourless. Type IIa diamonds can be coloured pink, red, or brown due to structural anomalies caused through plastic deformation during crystal growth.||
The flawless 12.03-carat 'Blue Moon' Fancy Vivid Blue diamond was sold at Sotheby’s in Geneva on November 19, 2015, for $48.4m. $4m a carat.
|The Hope Diamond is 45.52 carats and is the largest deep-blue diamond known. The stone can be traced to Golconda and is considered by many to be the most famous diamond in the world. Now on permanent display at the Smithsonian Natural History Museum in Washington, D.C. It is a Type IIb diamond and exhibits red phosphorescence after exposure to ultraviolet light. The diamond is notorious for supposedly being cursed.|
|The Wittelsbach-Graff is a 31.06-carat, Fancy Deep Grayish Blue diamond with an IF clarity and an unusual cut with 82 facets. The stone sold in 2008 for $24.3 million.|
A 13.22 carat pear-shaped Fancy Vivid blue flawless diamond sold at Christie's Geneva on May 14, 2014 for $ 24m, setting a new world auction record at the time for a blue diamond. It was renamed 'The Winston Blue'.