The Gemological Institute of America (GIA) recently examined a 2,488.32-carat gem-quality rough Lucara Diamond Corp. recovered last year.
Lucara found the stone in August 2024 at its Karowe mine in Botswana, the GIA said last week. The lab analyzed the large diamond and 1.50 carats of fragments that broke off when the miner cleaned it. The diamond consists of several large, gem-quality blocks with few inclusions, the laboratory found.
“[It’s] a single gem-quality crystal, type IIa diamond with no detectable nitrogen,” said Wuyi Wang, GIA vice president of research and development. “It is the largest known single-crystal diamond in existence and undoubtedly formed much deeper within the earth than the majority of diamonds.”
Lucara named the stone, weighing nearly 500 grams, Motswedi, which means water spring or source in Botswana’s national language, Setswana. Since its 2012 launch, the Karowe mine has gained global recognition for yielding large and high-quality diamonds of outstanding rarity, the GIA commented.
“This is undoubtedly a diamond of great historical importance,” said Tom Moses, GIA executive vice president and chief research and laboratory officer. “I have been fortunate to examine many significant, large and very rare diamonds, but I have never seen a gem-quality diamond of nearly this size.”
This is the second-largest diamond ever found. The largest was the 3,106-carat Cullinan, extracted in South Africa more than a century ago.
Image: The 2,492-carat rough diamond. (Lucara Diamond Corp.)