Firestone Diamonds' recent diamond sale achieved sales worth $1.4m, with 7,111 carats sold in all.
25 companies attended the auction, which saw 4,850 carats sold from Firestone's Liqhobong Mine in Lesotho, averaging $181 per carat, an 85% improvement on prices from December 2010.
The BK11 mine in Botswana sold 2,241 carats at $230 a time, a 30% increase on December's figures.
Chief executive Tim Wilkes commented: "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."
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