Sales of rough diamonds rose sharply during the first six months of this year, according to the group which supplies two thirds of the world with unpolished gems.

"The diamond industry began the year in a positive mood following better than expected Christmas season retail sales of diamond jewellery," De Beers said.

Sales of uncut gems reached $2.84bn during the period, up 8.5% from $2.62bn a year earlier.

The rise was partly credited to growing activity among diamond cutters gearing up to supply retailers whose stocks of diamonds were beginning to run low.

Crucial US market

Analysts had expected the sales rise, which marked a turn-around from a 21.5% fall in sales during 2001 as a whole.

Increasing diamond sales were seen by some as a sign that demand for luxury goods was heading for a recovery after being hit by the global economic weakness.

But De Beers insisted that "prospects for the remainder of the year will depend on the state of the global economy and consumer confidence".

Recovery in the US, where the firm makes half its sales, were "particularly" important, the firm said.

Shares in Anglo American, the diversified mining group which owns 45% of De Beers, rose 2.5% following the sales announcement.

De Beers is also owned by the Botswana government and by the wealthy South African family, the Oppenheimers.