The world’s largest blue diamond, the De Beers Cullinan Blue, has been sold at auction for $US57.47 million ($AU80.96 million) at Sotheby’s in Hong Kong. Source: De Beers

Discovered in April 2021 at the Cullinan Mines in South Africa by UK-based Petra Diamonds, the diamond was part of the special tender purchased by De Beers and diamond manufacturing firm Diacore for $US40.2 million ($AU55.79 million). Source: Sotheby's

The Cullinan Blue was originally a 39.34-carat Type IIb rough recovered from the South African Cullinan diamond mine in April 2021 Source: Petra Diamonds

Wenhao Yu, Sotheby's