Big Number $57.5 million. That’s how much the 16.63-carat Oppenheimer Blue, sold for at auction in 2016. It holds the record for the most expensive blue diamond.

The world’s largest blue diamond ever to come to auction has sold for 450,925,000 HKD, or $57.5 million. Named “The De Beers Cullinan Blue,” the massive 15.10-carat step-cut gem sold at ...

Some research is best done behind heavy, locked doors. When geologist Jeffrey Post recently embarked on an experiment involving the Hope Diamond, at 45.52 carats, the world’s largest deep-blue diamond ...

The “Bleu Royal” diamond set upon a ring went under the hammer for $43.8 million (CHF 39,505,000) at Christie’s auction in Geneva on Tuesday, the Associated Press, CBS News and Reuters reported.

GENEVA -- Sotheby's says a rare blue diamond has sold for a record 48.6 million Swiss francs or $48.5 million at a Geneva auction, including fees. The 12.03-carat "Blue Moon" Diamond is said to be ...

The Okavango Blue Diamond was discovered in 2018 at the Orapa mine in Botswana. The 20.46-carat gem is about the size of a plump almond. D. Finnin/AMNH ...

A 7.59-carat round fancy vivid blue diamond is being offered as the top lot in Sotheby’s Hong Kong Magnificent Jewels and Jadeite sale scheduled for October 7 at the Hong Kong Convention and ...