A white diamond the size of a small egg has sold for 30.6 million US dollars (£19 million) at a Hong Kong auction, although a blue diamond that was the night's other highlight with a 19 million dollar (£11.8 million) estimate failed to sell.
Two phone bidders competed for the 118-carat white diamond from Africa in six minutes of measured bidding until one dropped out in the Sotheby's jewellery auction, part of autumn sales of art and collectibles by the firm and its rivals.
The twice-yearly ritual in Hong Kong draws wealthy collectors from mainland China and other Asian countries and has made the city one of the world's busiest auction hubs.
The "flawless" white oval diamond, mined and cut two years ago, went for more than the previous record of 26.7 million dollars (£16.5 million) for a white diamond set in May at Christie's in Geneva.
The stone, which weighed 299 carats when it was found in the rough in 2011, is the largest and most significant such diamond graded by the Gemological Institute of America. Sotheby's says it was discovered in southern Africa but will not name the country because the seller wishes to remain anonymous.
The auction's other highlight, a 7.6-carat flawless, round, vivid blue diamond, failed to reach its reserve price.
The two gems were among 330 lots of rare jewellery that fetched a total of 95 million dollars (£59 million), although this was 15 million dollars (£9.3 million) less than expected.
"Hong Kong has in the last few years pulled itself up alongside Geneva and New York as one of the three major selling centres at auction" for diamonds, said Quek Chin Yeow, deputy chairman of Sotheby's Asia and an international diamond expert.
But he added that the results should not be taken as an indicator of how wealthy Asians are being affected by economic trends such as China's slowdown. Such stratospheric prices can only be afforded by the super rich, who he said are mostly immune from such fluctuations.
The world record price for a jewel at auction was set in 2010, when London jeweller Laurence Graff paid 46 million dollars (£28.5 million) for a "fancy intense pink" diamond weighing 24.8 carats.
That record could be blown away in November when Sotheby's puts a pink 59.60-carat diamond on the block which is expected to fetch more than 60 million dollars (£37 million) in Geneva.