Stellar Diamonds (LON:STEL) said it was delighted with its latest diamond auction of stones from Baoule in Guinea, which brought in sales of US$505,000.
It was through the online auction eDiamond platform and brings overall sales for 2015 of more than US$922,000 - of which US$700,644 comes from trial mine evaluation of Baoulé.
Six lots totalling 48.12carats of more than 5 carat stones sold for US$3,510.17 per carat, the firm said.
Stellar's chief executive Karl Smithson said: "The presence of larger, high value stones and the stability in the rough diamond market has resulted in an average price of US$156 per carat for the latest Baoulé "run of mine" parcel."
He added: "Trial mining is on-going and further diamond sales are targeted for the coming year."
The firm is targeting from trial mining 15,000 carats for sale and valuation.