Gem Diamonds has sold a pair of diamonds recovered last month from its Letseng mine in Lesotho for a combined 12.3m dollars.A rare 12.47 carat blue diamond fetched $603,047 per carat or a total of $7.5m. The mining group also sold a 82 carat exceptional quality white diamond for $4.8m.Gem Diamonds Chief Executive Clifford Elphick said: "We continue to expect recovery of such high quality diamonds as mining at Letseng continues to focus more on the higher grade, higher value satellite pipes towards the end of 2013 and 2014."Gem Diamonds owns 70% of the Letseng mine with the Government of the Kingdom of Lesotho owning the rest. Since it took control in 2006 the mine has produced four of the top 20 largest white gem quality diamonds on record.TB