$20mn diamond found in South Africa!

South Africa's Cullinan mine, the source of the world's biggest diamond, has produced yet another unusually large, high-quality diamond. The 507-carat gem was found alongside three more rough diamonds.

South Africa's Cullinan mine, the source of the world's biggest diamond, has produced yet another unusually large, high-quality diamond, the mining company that made the find announced Tuesday.

Petra Diamonds said the 507-carat gem was found alongside three more rough diamonds found at the mine on September 24. It was being subjected to expert analysis, but was being hailed by industry experts as one of the 20 largest high-quality rough diamonds ever found worldwide.

"Initial indications are that it is of exceptional colour and clarity, which suggest extraordinary potential for its polished yield," Petra Diamonds CEO Johan Dippenaar said.

The legendary 3,106.7-carat Cullinan Diamond - the world's largest ever gem-quality diamond - was recovered at the mine, near the city of Pretoria, in 1905. It was sold and became part of Britain's Crown Jewels.

South Africa's diamond industry is dominated by world leading mining company De Beers, which sold the then 104-year-old Cullinan Diamond Mine to the Petra Diamonds for around $150 million in 2007.