De Beers sold rough diamonds with a provisional value of $450 million in the 10th sales cycle (Global Sightholder Sales and Auction Sales) of 2017.
The mining giant said that there had been a continuation of good demand heading towards the end of the year.
De Beers Group CEO Bruce Cleaver said: "The tenth sales cycle of the year saw the continuation of good demand for De Beers rough diamonds as we head towards the end of 2017.
"Demand was broadly stable on the levels seen in Cycle 9, with sales slightly ahead of the equivalent period in 2016.”
De Beers added that in the ninth sales cycle last month, sales came to $466 million.
The December figure compares with $422 million in the year-earlier sale.
