A 603-carat white diamond has been found at the Letseng mine in Lesotho. The mine’s joint owners, South Africa’s Gem Diamond Mining and the Lesotho government, will put the diamond up for sale in Antwerp on October 4th. That day marks the 40th anniversary of the Kingdom of Lesotho and its independence from British rule.
The diamond, named the Lesotho Promise, is the largest diamond reported this century and ranks as the 15th largest diamond ever found. The previous largest diamond found at the Letseng mine was the 6.01 carat Lesotho Brown in 1967.
The Letseng mine is the world’s highest operating diamond mine, located 3.1 kilometers above sea level where temperatures reach -20 degrees Centigrade. The mine also has the highest percentage of large diamonds (over 10 carats) of any known kimberlite mine while having relatively low carat weight per ton of ore production. The mine has produced four diamonds over 500 carats since it started operations and numerous stones over 100 carats in weight.
Letseng’s two kimberlite pipes contain an estimated 2.3 million carats of economically mineable diamonds, which would take 25 years to mine.