Petra has found four stones over 100ct this year, including a 452.1ct D-colour Type II A diamond, called ‘The Legacy', recovered at the end of March.
It said this was the third large Type II D-colour gem found since the beginning of March.
The 209.9ct and 425.1ct stones will be on sale during the company's next sales cycle in South Africa this quarter, with viewing appointments to be made with head of sales and marketing, Greg Stephenson.
Petra said the latest recovery showed the prevalence of large, good quality stones in the Cullinan orebody, with "an improved incidence of large and high-value stones as the C-Cut Phase 1 block cave progresses across the footprint".
