World's Largest Yellow Diamond Fetches £6.8m

The world's largest known yellow diamond has been sold at auction for over £6.8m.

Auction house Sotheby's had estimated that the pear-shaped Sun-Drop Diamond would fetch between \$11-15m (£7-9m) at auction in Geneva.

It was bought by a telephone bidder who wished to remain anonymous.

The diamond was sold by New York-based company Cora International, which discovered the jewel in South Africa last year.

Gemologists rate the 110.3 carats diamond as fancy vivid yellow - the highest possible colour grading.

The colour in yellow diamonds is caused by nitrogen impurities trapped within carbon molecules and hardened over the course of millions of years.

The sales price does not include the auctioneer's commission and any taxes the buyer might have to pay.

"It sold for a record for a yellow diamond ... It was exactly within our expectation for this spectacular stone," Sotheby's auctioneer David Bennett said.