It appears as though 2018 is slated to be another year for large diamonds as both Gem Diamonds and Lucapa announced major large-size finds from their Lesotho and Angola mines respectively.
Gem Diamonds announced that it had unearthed two D-colour Type IIa diamonds weighing 117 and 110 carats from its Letseng mine in Lesotho. The Letseng mine is a known source of large stones and the new finds follow the seven stones larger than 100 carats unearthed in 2017, five in 2016 and a dozen in 2015. Gem Diamonds sold a 357-carat stone for $19.3 million in 2015. In 2006, it unearthed the 603-carat Lesotho Promise.
At an elevation of 3,100 metres (10,000 feet), Letseng is the highest diamond mine in the world. Despite having an extremely low ore grade of less than 2 carats per 100 tons, the mine’s large-diamond fines have given it one of the highest returns in terms of dollar value per carat.
Lucapa Diamond Company also announced that it had discovered two large diamonds — one weighing 103 carats and the other 83 carats — at its operations in Angola. Lucapa’s biggest-ever find was a 404 carat stone that sold for $16m in 2016.