Petra finds 20.08-carat blue diamond at flagship Cullinan mine

South Africa’s Petra Diamond has found yet another big rock at its iconic Cullinan mine, one of the many coloured diamonds it has unearthed at the operation this year.

The exceptional 20.08 carat blue gem quality diamond Type IIb demonstrates that Cullinan remains a significant source of rare blue diamonds, and confirms the ability of the mine’s plant to recover the full spectrum of precious stones, Petra said.

In April this year, the company found a 424.89 carat exceptional D colour Type IIa diamond at the same mine. The stone was sold the next month for just under $15 million.

In 2015, Petra sold “The Blue Moon of Josephine”, a 29.6 carat blue diamond, for $48.5 million, marking a world record price per carat at auction for any diamond at the time.