A rare blue diamond in the shape of Africa weighing more than 41 carats has been recovered from South Africa’s renowned Cullinan Mine

A rare blue diamond weighing more than 41 carats has been recovered from South Africa’s renowned Cullinan Mine, a discovery that has reignited global attention on one of the world’s most storied diamond producers and could fetch as much as R655 million once polished.

Petra Diamonds, which operates the Cullinan Mine about 20 miles east of Pretoria, confirmed the recovery of a 41.82 carat Type IIb blue diamond, describing the rough stone as being of exceptional quality in both colour and clarity. Specialists are still analysing the gem to determine the best cutting approach and eventual sale strategy.

Type IIb diamonds are among the rarest gemstones found in nature, accounting for less than one tenth of one percent of all diamonds. Their distinctive blue colour is caused by trace amounts of boron incorporated deep within the earth, with the stones forming at extreme depths before volcanic activity brings them closer to the surface.

The Cullinan Mine occupies a unique place in diamond history. It was here, in 1905, that the Cullinan Diamond, the largest gem quality rough diamond ever found, was discovered. That historic stone was cut into nine major gems, several of which remain part of the British Crown Jewels. Since then, Cullinan has built a reputation for producing exceptional blue diamonds, including the De Beers Cullinan Blue, which sold for $57.5 million in 2022. A similarly sized blue diamond recovered in 2021 later achieved a price exceeding $40 million.

Petra Diamonds reports that the mine has produced between 1.4 and 1.9 million carats annually over the past five years. Discovered in 1902, Cullinan is expected to remain in production until at least the 2040s.

The latest find comes at a difficult moment for the global diamond industry. Natural diamond prices have faced sustained pressure in recent years, driven by the rapid growth of lab grown alternatives, shifts in consumer spending, fewer weddings, and broader economic headwinds. According to industry data, prices for one carat natural diamonds fell by as much as 26 percent between 2022 and 2025.

Against that backdrop, the recovery of a high value blue diamond is expected to draw renewed interest from collectors and investors, particularly in African and international luxury markets. Petra Diamonds has not yet indicated when the stone will be offered for sale, but industry observers will be watching closely as analysis and cutting plans progress.

Large rough stones of this nature are typically cut into multiple smaller diamonds before being set into high end jewellery. Recent examples include major luxury collections built around gems sourced from a single exceptional stone, highlighting the enduring allure and commercial potential of rare natural discoveries such as Cullinan’s latest blue diamond.