Huge rough diamond sells for $ 10.4 million

LONDON, Nov 15 (Reuters) One of the largest rough diamonds ever found was sold for .4 million and is expected to be transformed into a polished stone of more than 100 carats.

The huge 493-carat rough diamond from Lesotho, the 18th largest ever recovered in the world, was sold to Graff Jewellers of London at a tender in Antwerp on Wednesday.

Miner Gem Diamonds said the diamond, recovered at Letseng le Terai mine in September, sold for an extraordinary price of ,000 per carat, against a global average diamond price of per carat.

The largest rough gem-quality diamond ever found was the Cullinan Diamond, found in South Africa in 1905, at 3,106.75 carats.

''The Letseng Legacy was named to reflect the growing legacy that the Letseng le Terai mine is creating as a producer of significant diamonds,'' Gem Diamonds said in a statement.

Letseng Diamonds, 70 percent owned by Gem Diamonds and 30 percent owned by the government of Lesotho, has now produced three of the world's top 20 diamonds, including the 603-carat Lesotho Promise.

Graff Jewellers were also the winning bidder for the Lesotho Promise in 2006.

A brilliant-cut white diamond, which weighs 84.37 carats, was sold at an auction in Geneva on Wednesday for nearly 18.2 million Swiss francs (.21 million) to Guess Jeans founder Georges Marciano, Sotheby's said.

That diamond was the second most expensive stone ever sold at auction, eclipsed only by the 100.10 carat ''Star of the Season'' diamond, which went for .5 million in May 1995.

REUTERS BJR DS1655