(IDEX Online) - Gem Diamonds has recovered its four and fifth +100-ct diamonds of the year at its Letseng mine, in Lesotho.The UK-based miner yesterday (30 October) announced it had found two "high quality" stones, both Type IIa D color diamonds, weighing 117.47 carats and 110 carats.Letseng, known as the highest dollar per carat kimberlite diamond mine in the world, saw its revenue from rough sales fall by 19 per cent to $71.6m in the first half of this year, partly because of fewer recoveries of high-value diamonds.Its long-term average, since 2008, has been eight +100-ct recoveries a year. Last year it recovered just four.Earlier this month Gem found a find is a 101.96-ct Type IIa diamond. In July it recovered a 163.91-ct yellow diamond and in March it recovered of a 122-carat D color Type II white diamond.The mine is 70 per cent owned by Gem and 30 per cent by the Lesotho government.Pic of the 117.47-ct recovery, courtesy Gem Diamonds