According to Sotheby's, the rare 15 carat jewel known as "The De Beers Cullinan Blue" sold at auction house Sotheby's in Hong Kong after an eight-minute bidding war between four hopeful purchasers.
An unknown bidder placed the winning bid, which exceeded the high estimate of $48 million.
In Hong Kong, a rare 15 carat blue diamond was auctioned for $57.5 million.
The unusual diamond was discovered at the Cullinan mine in South Africa in 2021, and it has risen to the top of the coloured diamond rankings.
According to a statement from Sotheby's, the gem was classified as "fancy intense blue" by the Gemological Institute of America (GIA), the highest colour grading given to less than 1% of blue diamonds submitted to the organisation.
In Hong Kong, a rare 15 carat blue diamond was auctioned for $57.5 million.
Only five stones larger than ten carats have ever been auctioned, according to Sotheby's. None have ever been larger than 15 carats, "making the appearance of this immaculate gem a historic event."
The De Beers Cullinan Blue almost missed setting the record for the most valuable blue diamond ever sold at auction with a final price of $57,471,960. That honour is still held by the 14.62-carat "Oppenheimer Blue," which sold for $57,541,779 in 2016, a difference of $70,000.