BBC News and Premier are reporting that an artisanal miner, who is apparently a Christian pastor, has discovered one of the world's largest rough diamonds in Sierra Leone's Kono district. If correct, and if it is gem-quality, the diamond, said to weigh 709 carats, would be one of the 20 largest gem-quality diamonds ever found - coming in at #13, right behind the famous 726-carat Jonker Diamond recovered at the Elandsfontein mine in South Africa on January 17, 1934, and just ahead of the 650.80-carat Jubilee Diamond, discovered in 1895 in South Africa. For a history of the world's largest rough diamonds and their stories, see Ehud Ayre Laniado's series, "A Tour of the World’s Largest Diamonds" (Parts I, II, III, IV, and V).
The new find in Sierra Leone is said to be locked up in Sierra Leone's central bank in Freetown. Premier reports the diamond was presented to the country's president who thanked the local chief for not smuggling the diamond out of the country, according to a statement from the president. President Ernest Bai Koroma said that Pastor Emmanuel Momoh would get "what is due" to him, but that any profits from the diamond will benefit Sierra Leone as a whole. There is no indication at this time whether it is a gem-quality stone.
The largest diamond ever found in Sierra Leone is the Star of Sierra Leone – 968.9 cts. Laniado writes: "The Star of Sierra Leone was discovered by miners on February 14, 1972 in the Diminco alluvial mines in the Koidu area of Sierra Leone. The gravels of the Woylie River have produced numerous large diamond finds in the more than 70 years of diamond mining in the area. At 968.9 carats (193.78g), the Star of Sierra Leone ranks as the fourth largest gem-quality diamond, and the largest alluvial diamond, ever discovered. On October 3, 1972, Sierra Leone’s then president, Siaka Stevens, announced that New York City jeweler Harry Winston had purchased the diamond for nearly $2.5 million. Cutting was entrusted to master cutter Lazare Kaplan, who spent more than one year planning the stone. For the first time ever, Mr. Kaplan cleaved the stone on live television in the United States, following which the diamond became a household name throughout America. Although the diamond was colorless, it did have internal inclusions that made cutting the stone complicated. It was initially cleaved and cut into 17 pieces, 13 of which were internally flawless. The largest polished diamond among them was initially cut into an emerald shape weighing 143.2 carats. However an internal flaw led to re-cutting, eventually resulting in a flawless pear-shaped diamond of 53.96 carats. Harry Winston later set six of the diamonds from the original rough stone into the Star of Sierra Leone Brooch.