Cullinan Mine Unveils 42-Carat Type IIb Blue Diamond Valued at $40 Million A rare blue diamond weighing 41.82 carats has been discovered at South Africa’s historic Cullinan Mine, reinforcing the site’s reputation for producing some of the world’s most exceptional coloured diamonds. Industry experts estimate the stone could fetch $30–$40 million at auction. Petra Diamonds, which operates the mine approximately 20 miles east of Pretoria, described the find as a “type IIb blue diamond of
![]()
