South Africa’s Petra Diamonds has found yet another big rock at its iconic Cullinan mine, the third coloured diamond over 100-carats since March that has been unearthed at the operation.

It is the third Type II D-colour gem-quality diamond weighing more than 100 carats recovered at Cullinan since MarchThe 209.9 carat, D colour, Type II gem-quality diamond is also the fourth such stone discovered by Petra so far this financial year.

It follows last month’s recovery of a 100.83 carat gem-quality diamond and a previous 6.12 carat Type II blue stone both found at Cullinan.

The company, which recently appointed former gold miner Richard Duffy as chief executive, said the stone would be included in its upcoming sales cycle, along with a 425-carat D-colour Type IIA diamond recovered on March 29.

Petra has been seeking to turn around its fortunes after piling up debt to expand Cullinan, which yielded the world’s biggest-ever diamond in 1905.

Shares in the company jumped on the news and were trading up 4.5% in London at 17.92p by 3:08 p.m. local