Diamonds are found in about a quarter of Sierra Leone in the south-east and east of the country, with the diamond fields cover 7,700 square miles. The main production areas are concentrated around the drainage areas of rivers in the Kono, Kenema and Bo Districts. In the Kono, Kenema, Bo and Pujehun Districts there are 1,700 artisanal mining licenses in operation.
In 2009 the government recorded exports of 400,480 carats (80,096 g) of diamonds, this included 143,620 carats (28,724 g) of industrial diamonds and 256,860 (51,372 g) of gem diamonds. This was an increase of 7.86 percent on the previous year which was a result of legislative changes, in the form of a new mining law, to enable fees and royalties to be collected more effectively and an increase in the amount of diamond mining. Diamond exports were worth US$ 78,373,900 in 2009 accounting for 59 percent of the country’s exports. The drop in the value of diamonds on the world market meant that the value of diamond exports decreased by 20.68 percent in 2009 compared to 2008.
The largest diamond found in Sierra Leone, and the third largest diamond in the world, was a 969.8 carat (194 g) rough diamond. It was found in 1972 and named the An-al of Sierra Leone.