(IDEX Online) - Gem Diamonds has recovered an exceptional Type II 245-carat diamond (pictured) from its Letseng mine in Lesotho.It's the third +100-carat stone in three weeks from the world's highest dollar per carat kimberlite diamond mine.London-based Gem recovered a 129-carat stone on 23 May at Letseng, the world's highest diamond mine, 3,100 meters above sea level in the Maluti Mountains. And a 125-carat diamond on 31 May.In April, Gem Diamonds reported a slight increase in quarterly revenue, up four per cent on Q4 2021 to $52.1m, and said it was confident about future prices.