HONG KONG (AFP).- A flawless fancy vivid pink diamond sold for a record US$17.7 million in Hong Kong late Tuesday, Sotheby's said.

The auction house said the internally flawless 8.41-carat stone had been expected to go under the hammer for up to US$15.5 million.

Quek Chin Yeow, deputy chairman of Sotheby's Asia, said the pear-shaped stone had "attracted keen competition before fetching a wonderful price of HK$137.88 million (US$17.77 million) and setting a world auction record for a fancy vivid pink diamond".

The buyer's identity was not immediately disclosed.

Internally flawless clarity is extremely rare in pink diamonds, and the auction house said this, in combination with its "fancy vivid" colour grading, made the stone "amongst the rarest and most desirable of coloured diamonds ever seen at auction".

Diamonds in the "fancy vivid" category are considered as having the highest possible concentration of colour.

QUEK Chin Yeow, Deputy Chairman and Head of Jewellery Department, Sotheby’s Asia, said, “Tonight we were thrilled to achieve consecutive per-carat price records for Kashmir sapphire first with the Cartier sapphire ring at HK$1,505,246 / US$193,975 per carat then again with a sapphire and diamond ring at HK$1,834,499 / US$236,404 per carat. The top lot of the night, a vivid purple-pink diamond ring mounted by Sotheby’s Diamonds, attracted keen competition before fetching a wonderful price of HK$137.88 million and setting a world auction record for a fancy vivid pink diamond. Also notable is a very fine icy multi-coloured jadeite ‘Guan Yin’ ornament which achieved HK$14.44 million and figures among the top ten lots of the sale. The highly anticipated Ballerina Butterfly brooch co-designed by Cindy Chao and Sarah Jessica Parker to benefit the New York City Ballet achieved HK$9.4 million.”

PREVIOUS RECORDS

• The previous world auction record for a fancy vivid pink diamond and record price per carat for a pink diamond were both achieved by a 5.00-carat fancy vivid pink diamond, which sold for HK$83,540,000 / US$10,776,660 ie. US$2,155,332 per carat in Hong Kong in November 2009.

• The previous record price per carat for a sapphire was achieved by a 28.18-carat Kashmir sapphire and diamond ring which sold for CHF4,478,544 / US$5,093,000 ie. US$180,731 per carat at Sotheby’s New York in April 2014.