A 910-carat diamond the size of two golf balls has sold for $40m (£29m), making it one of the most expensive in history.
Gem Diamonds found the huge stone – at its Letseng mine in Lesotho earlier this year.
Named the Lesotho Legend, it is the fifth-largest diamond ever discovered and the $40m sale price is the most that Gem has received for a stone.
The London-listed mining firm announced it had sold the “exceptional quality” gemstone to an unnamed buyer in Antwerp.
The diamond is classified as a D colour Type IIa diamond, meaning it has almost no impurities.
Rival company Lucara Diamond achieved a record $63m for an 813-carat stone last year and $53m for the 1,109-carat diamond it found at the same time, which was the second-biggest in history.
Clifford Elphick, Gem Diamonds’ chief executive officer, said: “We are delighted with the outcome of the sale of this iconic diamond, which demonstrates the exceptional quality of the Lesotho Legend itself, as well as reaffirming the unique quality of the Letseng diamond production.”
The Letseng mine produces stones of the highest average size of any mine in the world.