The discovery reinforces the mine’s reputation as a source of some of the world’s most exceptional coloured diamonds.
Petra Diamonds, which operates the site about 20 miles east of Pretoria, described the find as a “41.82 carat type IIb blue diamond of seemingly exceptional quality in terms of both its colour and clarity”.
Type IIb diamonds are among the rarest in nature, comprising less than one-tenth of one percent of all diamonds.
The Cullinan Mine holds a special place in gem lore. It was the source of the legendary Cullinan Diamond, discovered in 1905, the largest gem-quality rough diamond ever found. That historic stone was cut into nine major gems, several of which are now part of the British Crown Jewels.
Johannesburg diamond dealer Gregory Katz, speaking to News24, said the latest find could command between $30 million and $40 million once final cutting and polishing decisions are made.
He explained that cutters will try to maximise the finished size, but “the finished, polished stone would be significantly smaller than the original rough diamond”.
“There is little doubt it is a significant find,” Katz added, underlining the rarity and potential market value of such stones.
The latest discovery is likely to draw renewed interest from collectors and investors alike, particularly in African and global luxury markets.
Petra Diamonds has not yet confirmed when the stone will go to market, but industry watchers will be closely tracking developments.
