Diamond magnate's rare stone goes under the hammer in Geneva

A 14.62-carat blue diamond owned by an architect of the modern diamond industry could fetch a record price at this week's Magnificent Jewels auctions in Geneva.

The dazzling rock previously belonged to the late Philip Oppenheimer, scion of the family that controlled the De Beers diamond mining company.

As chairman of a powerful cartel called the Central Selling Organization, Oppenheimer -- who died in 1995 -- tightly controlled the international diamond trade and helped make it extremely lucrative.

His success will be on full display Wednesday when Christie's puts "The Oppenheimer Blue" under the hammer at the ultra-luxurious Four Seasons des Bergues hotel overlooking Lake Geneva.

Christie's has valued the Oppenheimer stone at between $38 million (34 million euros) and $45 million, giving it an outside shot of breaking a record set by rival auction house Sotheby's in November.

The 12.03-carat Sotheby's diamond was bought for $48.4 million by Hong Kong billionaire Joseph Lau, who a day earlier scooped up a 16.08-carat pink diamond for a comparatively modest $28.5 million.

The property tycoon, who was convicted of bribery in Macau last year, named both stones after his daughter Josephine.

Christie's jewel expert Jean-Marc Lunel told AFP that The Oppenheimer Blue's price could top what Lau paid for "The Blue Moon of Josephine".

"It's a fabulous diamond, the most beautiful I have even seen and it could set a record price," he said.

According to Christie's, the Oppenheimer diamond is the largest ever sold at auction in the exclusive Fancy Vivid Blue category, which groups rare gems of exceptional colour and clarity.

But, there is always a chance that the jewel will not even meet its estimated floor price.

That happened last month when a 9.54-carat blue diamond ring once owned by American child star Shirley Temple failed to sell at auction in New York after bidding closed at $22 million, below the reserve price.

Christie's has valued its total of 280 lots up for auction on Wednesday at $113 million. The collection includes 46 pieces from German-born princess Gabriela zu Leiningen, who was married to the Aga Khan.

Sotheby's kicks off Geneva's Magnificent Jewels week on Tuesday with a 495-lot offer valued at $140 million, the highlight of which is a 15.38-carat pink diamond.