A 185-carat rough diamond has been discovered in the enclave country of Lesotho.
Gem Diamonds found the precious stone in the Letseng mine towards the end of October 2010.
The rock in its current state weighs more in carats than the famous Pink Panther diamond ring and Hope diamond necklace combined.
It is the firm's second significant finding at the site since August 2010, when miners uncovered one weighing 196 carats.
Clifford Elphick of Gem Diamonds stated: "Letseng is one of the world's truly extraordinary diamond mines and its reputation is well deserved given the frequency with which it produces remarkable diamonds."
He added that the mine has been the source of three of the world's largest diamonds since the company acquired it in 2006.
The organisation, which has assets in eight countries, has more than 150 years of experience in diamond mining
According to the firm, first inspections have revealed that the mineral will present top quality colour and clarity and is expected to bring in a generous price per carat.