Yellow Sun-Drop diamond goes for $10.9m at Sotheby's

Video caption, The 大象传媒's Imogen Foulkes: "Despite the downturn, jewellery sales in Geneva have been brisk"

An extremely rare yellow diamond known as the Sun-Drop has sold at auction in Geneva for just over $10.9m (拢6.8m).

Sotheby's auctioneer David Bennett said the sum - paid by a telephone bidder who preferred to stay anonymous - set a world record for a yellow diamond.

The 110.3 carat pear-shaped diamond is said to be one of the largest diamonds ever to appear at auction.

Discovered in South Africa last year, it was sold by New York-based Cora International.

The diamond was certified by gemologists as "fancy vivid yellow", the rarest and most desirable colour for a yellow diamond, Sotheby's had said.

The colour is the result of traces of nitrogen trapped within carbon molecules and hardened over the course of millions of years.

The diamond had a pre-sale estimate of $11-15m. With commission and taxes, the buyer paid out $12.36m.

"It sold for a record for a yellow diamond... It was exactly within our expectation for this spectacular stone," Mr Bennett told reporters after the sale.