Geneva - An exceptional 12.03-carat diamond dubbed "Blue Moon" was sold in Geneva for a new world record of 48.6 million Swiss francs (S$68.7 million) on Wednesday, auction house Sotheby's said.
The vivid diamond, described as flawless by experts, was bought by a private collector from Hong Kong, who immediately renamed it "The Blue Moon of Josephine".
The record-breaking sale comes a day after rival auction house Christie's sold a rare 16.08-carat pink diamond, the largest of its kind to ever appear at auction, for US$28.5 million, narrowly beating pre-sale projections.
That was also won by an Asian buyer, who re-baptised it "Sweet Josephine".
David Bennett, head of Sotheby's international jewellery division, said the "Blue Moon" sale broke several records, making the gemstone "the most expensive diamond, regardless of colour, and the most expensive jewel ever sold at auction".
The rock, set in a ring, went under the hammer for 43.2 million Swiss francs, with the final sale price amounting to 48.6 million Swiss francs including fees.
It also fetched the highest-ever price per carat, he said, with the buyer shelling out 4.02 million Swiss francs per carat.
The previous world record for a jewel sold at auction was held by the 24.78-carat "Graff Pink" diamond, which was sold by Southeby's for US$46.2 million in November 2010.
Two bidders were locked in a telephone bidding war for eight minutes before the hammer went down, with the precious jewel staying within its pre-sale estimate of US$35-55 million.
The diamond was discovered in South Africa in January last year and was the largest cushion-shaped blue stone in the fancy vivid category to ever appear at auction.
Experts say the market for coloured diamonds has grown increasingly robust and both the blue and pink diamonds garnered a lot of attention in the run up to this week's jewel sales in Geneva.