RAPAPORT... Gem Diamonds reported a rise in first-quarter sales amid strong demand and the sale of high-value rough from its Letšeng mine in Lesotho.Revenue climbed 19% to $52.1 million during the three months ending March 31, the company said last week. Sales volume grew 6% to 28,461 carats, while the average price increased 12% to $1,831 per carat.Prices were higher on a like-for-like basis than...
