Significant diamond price increases helped AIM-quoted Firestone Diamonds pocket $1.4m of the sale of 7,111 carats, after the completion of its first diamond sale of 2011.The group sold 4,850 carats from its Liqhobong mine in Lesotho at an average price of $181/carat, and a further 2,241 carats from its BK11 mine in Botswana were sold at an average price of $230/carat: these prices were 85% and 30% higher than in December, respectively."The higher prices reflect the quality of production from the mines as well as the continued strength of the rough diamond market. We expect to see significant further increases in prices achieved for production from Liqhobong and BK11 as production at both mines increases in 2011," said chief executive officer Tim Wilkes.Demand from local and international buyers was extremely strong, with a total of 25 companies attending the tender, according to Firestone.---bc