Anglo American-owned diamond specialists De Beers said that the value of rough diamond sales rose to $425m (£324.5m) in the tenth cycle of 2019.
The sales marked a $25m improvement on cycle nine in November, which in turn had the highest levels since June.
However, the figures were down roughly 20 per cent on the same period in 2018, when the firm sold $544m of diamonds.
Bruce Cleaver, De Beers’ chief executive, said: “Following continued polished diamond price stability in the lead up to the final sales cycle of the year, we saw further signs of steady demand for rough diamonds during sight 10.”
2019 has proved a challenging year for diamond sales, with a combination of oversupply, ongoing trade tensions and increased sales of lab-grown diamonds all responsible for the fall in sales.
The lower demand for the precious stones saw De Beers cut its production from 35.3m carats to 31m carats for 2019.
De Beers markets diamond production at 10 sights throughout the year, at which buyers are shown boxes containing a range of stones with prices attached.
According to Bloomberg, in August this year’s slump in the global market forced the firm into giving buyers “unprecedented flexibility” in being able to reject the diamonds offered to them as well as in negotiating prices.
De Beers also cut prices across the board by about five per cent in November, as purchases by cutters and polishers have declined due to restrictions in the availability of credit.