Fashion Blog: Cullinan blue diamond

Petra Diamonds has sold a stunning blue diamond from the Cullinan mine for a record $ 9.4 million highest auction price every for a fancy vivid blue diamond at Sotheby's in Geneva.

The rectangular-shaped blue stone, mounted on a platinum ring, is the rarest to enter the international market this year.

An anonymous phone bidder won after a 15-minute bidding war, and has yet to name the gem.

The flawless diamond, which is smaller than a penny, was the centrepiece of Sotheby's semi-annual sale in Geneva.

The stone sets a record price per carat for any gemstone sold at auction of $1,349,752, Sotheby's said.

The blue diamond bucked a trend at the auction, where rings, bracelets and necklaces on offer sold, on average, for almost 10 per cent less than expected.

Diamantaires said the record price obtained for the exceptional blue diamond at Sotheby's will help fuel consumer confidence in the international market.

The blue diamond was cut from a 26.58-carat rough stone that Petra discovered in 2008 at its Cullinan diamond mine in South Africa.

The Gemological Institute of America (GIA) graded the 7.03-carat stone as fancy vivid blue and internally flawless. Sotheby's noted that this blue diamond beat out the previous most expensive fancy vivid blue diamond of 6.04 carats, which was sold by Sotheby's for almost $ 8 million in Hong Kong in October 2007.

The third most expensive fancy vivid blue diamond sold was also a 3.7-carat pear-shaped diamond. It was sold by Sotheby's for almost $5 million in Geneva a year ago.

According to industry experts, the demand for big-sized stones is fast picking up in the international markets like Hong Kong, Japan, China, the US etc. There are many diamond manufacturers in Surat and Mumbai, who have ventured into the manufacturing of big-sized stones solitaires.