Diamond giant De Beers said Tuesday it sold $540 million (498 million euros) of rough diamonds in its first sale of the year, more than doubling the earnings of its final sale of 2015.

"Rough diamond sales during the first cycle of the year improved significantly compared with the final sales cycle of 2015," the company said in a statement, crediting increased demand from cutting and polishing factories following a successful holiday retail season.

Last August De Beers, the world's biggest diamond producer, lowered prices by as much as nine percent to boost sales.

The move came amid a wider commodities slump, with global stock markets plunging over fears of an economic slowdown in China, a key growth sector for diamond sales.

The price cuts followed a squeeze in production that failed to fuel demand for diamonds.

According to Bloomberg News, De Beers lowered its output target three times last year -- and is now at a six-year low -- and cut prices as much as 7 percent at the 2016 sale.

The result was a haul more than double the $248 million made in the final sale of 2015.

"We are encouraged by the result of the first sales cycle of 2016, and will keep working closely with our customers to deliver sustainable improvements in the diamond industry in 2016," chief executive of the De Beers group Philippe Mellier said in the statement.

De Beers, founded in South Africa in 1888, is majority-owned by Anglo American.

As well as China, India is seen as a key growth market for diamonds, which tap into burgeoning middle-class aspirations.