(IDEX Online) - Gem Diamonds announced a 13 per cent increase in Q1 rough sales from Letseng, in Lesotho, the highest dollar per carat kimberlite diamond mine in the world. It raised $36.7m.The London-listed miner said it achieved an average $1,431 per carat during the quarter to 31 March 2023, virtually unchanged from the previous quarter.The highest price paid was $282,889 per carat for a 6.63-carat pink diamond, the third highest dollar per carat achieved for a Let?... ?eng rough diamond.A 58.07-carat Type IIa white diamond sold for $34 441 per carat, the company said in a trading update. Seven diamonds sold for more than $1m each during the quarter, A 122 carat Type II white diamond recovered in Q1 will be sold in Q2.The total number of carats sold during the quarter was up 14 per cent to 25,687 and sales were up 13 per cent to $36.7m.In March Clifford Elphick, the company's CEO, said: "Demand for Letseng's large, high-value diamonds remains strong. The re-opening of China, the second largest diamond market, is expected to pave the way for a rapid rebound in economic activity, which bodes well for diamond prices in 2023."Gem Diamonds, which owns 70 per cent of the Letseng mine, in the process of selling its 100 per cent share in its other mine, Ghaghoo, in Botswana, which has been mothballed since 2019, to Botswana-based Okwa Diamonds, owned by Vast Resources.File pic shows a 122-carat D color Type II white diamond recovered at Letseng