Sharjah24 – AFP: The Rock, the biggest white diamond ever auctioned, sold for 21.7 million Swiss francs ($21.9 million) on Wednesday, far short of the record for such a jewel.

The 228.31-carat stone, larger than a golf ball, was sold in Geneva by Christie's auction house.

There had been high hopes that The Rock would smash the world record for a white diamond, which stands at $33.7 million, a sum fetched in Geneva in 2017 for a 163.41-carat gem.

But the bidding, which started at 14 million Swiss francs, ground to a halt after two minutes at 18.6 million, with the price rising to 21.7 million once the buyer's premium was added on.

The pre-sale estimate had been 19-30 million Swiss francs.

The Rock, a perfectly symmetrical pear-shaped diamond, was sold by an unnamed owner from North America. It was bought by a private collector bidding by telephone.

Rahul Kadakia, Christie's international head of jewellery, brought down the hammer to applause in the sale room in the plush Hotel des Bergues.

Diamonds are graded in colour from D to Z and Kadakia told AFP that despite falling short of the overall record, The Rock had set a new world record price per carat for a G-colour diamond.

"When you look at the price per carat -- 100,000 per carat -- this is the level of a D colour diamond, and we achieved that for a G colour diamond. So in fact, we're very pleased as are the sellers, as is the buyer."