Lucara Diamond has reported revenues of $38.1m for the second quarter of this year, compared to $71m for the same period in 2014.
Net income for the period declined to $8.6m in Q2, compared to $15.6m in the year-ago period.
The company said revenues totaled $138.1m for the year to date after the last month’s exceptional stone tender.
Lucara sold two largest diamonds, totaling 610 carats, sold for $37.1m or $60,639 per carat.
The company has year to date achieved diamond sales an average price of $662 per carat, which is 2.8% higher than the full year 2014, including the exceptional stone tender revenues.
The company completed the Karowe mine plant optimization project on schedule and within budget.
Lucara Diamond president and chief executive officer William Lamb said: "We are pleased to have achieved strong operational results and cash flows during the year, highlighted by our exceptional stone tender which the market continues to recognize as offering very high quality diamonds.
"The Company is currently in a very strong financial position despite what has been a more difficult period for the diamond industry."
Lucara Diamond’s assets include the Karowe mine in Botswana, two stone exploration licenses in Botswana and the Mothae project in Lesotho.
The company owns 100% interest in Karowe mine, which is in production. The 75% owned Mothae project is currently being sold.