De Beers boosts 2008 rough diamond prices 8.5 pct

LONDON, April 25 (Reuters) - De Beers, the world's biggest diamond producer, has increased prices of rough diamonds it sells to selected clients by an average of 8.5 percent so far this year, it said on Friday.

De Beers, 45-percent-owned by mining group Anglo American (AAL.L), said in February that it expected a rebound in its rough diamond sales this year after a dip in 2007.

They fell 3.7 percent to $5.9 billion in 2007, but supply shortages were expected to keep prices strong and help to lift the 2008 sales figures, De Beers had said.

De Beers' marketing arm, the Diamond Trading Company, issued a statement this week to its tightly-screened clients -- sightholders -- giving an update on prices.

It was issued ahead of the next "sight" due next week, one of 10 week-long events during the year at which the DTC markets rough diamonds.

"Overall, the cumulative effect of the sight by sight changes to our list prices over the first four sights of 2008 will have been an average of +8.5 percent," the notice said, which was provided to Reuters by e-mail.

Next week's sight will be the fourth in 2008.

"All areas have shown some price growth and the increases have been concentrated in rough boxes where the demand is strongest and the largest polished price increases have occurred."

In February, De Beers Managing Director Gareth Penny said the outlook for rough diamond prices hinged partly on the economy in the United States -- the world's biggest diamond jewellery market with half of total sales.

But even if a U.S. downturn dampened sales for cheaper products there, healthy demand was due to continue in China, India and the Middle East, he added at the time.

De Beers, which controls around 40 percent of the diamond market, posted flat output of diamonds last year at 51 million carats and a steady result is expected in 2008.

One reason De Beers sales dipped last year was due to an anti-trust deal with the European Union that has been phasing out distribution of gems by the DTC from Russian state diamond miner Alrosa.

DTC is due to sell $400 million of Alrosa diamonds in 2008, down $100 million from last year. (Reporting by Eric Onstad; Editing by Andrew Hurst)