Firestone Diamonds (LON:FDI) generated US$5.1mln from diamond tenders in October and November at Gaborone and Antwerp.
Total sales were 63,991 carats, with over 47,000 sold in October’s sale at an average price of US$75 per carat and raising US$3.5 mln.
November’s sale was 16,300 carats but the average price rose by 28% to US$96 due to higher quality diamonds from the K2 unit of the main pipe at the Liqhobong mine in Lesotho.
The November tender was the first at the Antwerp World Diamond Council tender house operated independently on behalf of the company by First Element Diamond Services. Eighty-four diamond buyers were present.
Tim Wilkes, Firestone’s chief executive, said: "The results of the tenders held in Gaborone and Antwerp are encouraging and in line with our expectations.
“The 28% increase in diamond prices achieved between October and November 2012 tenders is primarily due to the higher quality, better shaped, unbroken white stones that were on sale in the November 2012 tender.
“These type 2A and high colour white stones were recovered from the upper benches of the K2 ore that was mined during the period leading up to the tender.
"Although this rock unit is lower grade (24 carats per hundred tonnes "cpht") than the higher grade K5 section of the mine (45 cpht), it consistently produces higher quality diamonds."