The Chloe sold for more than $21 million.
Amid fears that the art market bubble is about to burst, diamonds are proving to be the auction houses' best friend.
In the past month, they have fetched record prices in sale rooms from Hong Kong to New York.
A stone described by Sotheby's as "the largest, purest,
white flawless brilliant-cut diamond ever bought at auction" was sold for £7.9 million ($21.4 million) last week to Georges Marciano, the founder of Guess Jeans, in Geneva.
It was the second highest price paid for a diamond at auction and the highest price a carat for a white diamond. Weighing 84.37 carats, the stone sold for £93,000 a carat.
Marciano has called the jewel the "Chloe Diamond" after his daughter.
In the same week, Christie's in Geneva sold the largest red diamond to come to auction for a record price of £1.3 million, £584,000 a carat.
Red and green diamonds are extremely rare and command the highest prices, followed by blue diamonds.
Next month, Christie's is holding a jewellery sale in London, the centrepiece of which will be a flawless pear-shaped diamond pendant, weighing 17.62 carats, estimated at £800,000 to £1 million. In the same sale, there are eight D-coloured diamonds (the purest colour) of which at least four are flawless.
David Warren, Christie's director of jewellery, London and Dubai, said prices for larger diamonds of four or five carats or above had increased by 40 to 60 per cent in the past two years and by 80 to 120 per cent in the past five years.
"There isn't enough supply to meet the demand. The diamond mines at the moment are not finding diamonds rough to cut very much over five carats.
"The other factor is the increased demand from all around the world. We've got a lot of Russian buyers coming into the market."
The diamond cutting process is very unforgiving - the Chloe Diamond lost 28 per cent of its weight when it was brilliant-cut.
"It was the paradigm of diamonds," said Mr Bennett.
The most expensive diamond in the world was the Star of the Season, weighing 100.10 carats, which Bennett sold at Sotheby's Geneva for £8 million in May 1995.
- Independent
