Blue diamond uncovered at Cullinan mine in South Africa.

A 41.28-carat blue diamond was found at the Cullinan mine, and Petra Diamonds says the Type IIb stone—reported by the company as 41.82 carats—is being analyzed to confirm its final size and quality.

A blue diamond weighing reported as 41.28 carats has been unearthed at the Cullinan mine in South Africa. The mine operator, Petra Diamonds Limited, said the stone is a Type IIb and is being analyzed to confirm its final size and quality; the company’s release described the stone as 41.82 carats. Blue diamonds receive their color from traces of boron and are among the rarest gem types. The Cullinan mine is known for historic large finds and has produced about 1.4 to 1.9 million carats annually in recent years. Known details: - Reported weight is 41.28 carats; Petra Diamonds described the stone as a 41.82-carat Type IIb in its release. - The diamond is undergoing laboratory analysis to determine final weight, clarity and value. - Blue coloration in diamonds is caused by boron, a factor that makes these stones uncommon. - The Cullinan mine was discovered in 1902 and is expected to continue producing gemstones into the 2040s. - The mine has produced notable blue diamonds before; the De Beers Cullinan Blue sold in 2022 for $57.5 million. - Grant Mobley, editor and gemologist, described the find as among the rarest and said it could be a record-setting stone once analyses are complete. Summary: Experts and the company report this as a potentially significant find pending laboratory results. Analysis will confirm the diamond’s final weight, clarity and market value. Further details will be released after those tests are complete.