The De Beers Blue The World’s Largest Blue Diamond Recently Sold for $57.5 Million

The gigantic 15.10-carat step-cut rock, dubbed “The De Beers Blue” has been classified as “fancy bright blue,” the best color grading by The Gemological Institute of America. Only around 1% of blue diamonds across the world achieve this feat, making it one-of-a-kind.

Only five stones larger than 10 carats have ever been auctioned, and none larger than 15 carats, according to Sotheby’s, making the emergence of this perfect diamond a momentous event in itself. It’s also the Gemological Institute of America’s biggest internally flawless step-cut bright blue diamond ever graded.

Petra Diamonds discovered the “De Beers Blue” as a 39.35-carat rough in April 2021 at its Cullinan mine in South Africa. Diacore purchased it and polished it to its current state. It is a once-in-a-generation stone, with its tremendous brilliant color and stunningly exquisite cut, and quite simply the best blue diamond of its size. The stone isn’t the most costly of its kind in the world, though; the 14.62-carat “Oppenheimer Blue” still holds that record.