(IDEX Online) - A flawless 10.59-carat diamond ring sold for $968,000 at Phillips Hong Kong, well above its pre-sale estimate of $700,000 to $850,000.The D-color type IIa Asscher-cut stone was cut from a 30.80 carat rough diamond recovered at the Letseng mine, Lesotho.Phillips said the 165-lot Jewels and Jadeite sale on Saturday (5 June) raised $6.8m in total, with 76 per cent sold by lot, but only 57 per cent sold by value.The auction house said there was strong demand for rubies, Kashmir sapphires and other high-quality colored stones, as well as D-color flawless diamonds.Graeme Thompson, worldwide head of jewellery at Phillips said: "This season's result achieved a 13% increase in value on the Spring 2020 auction of Jewels and Jadeite. "We welcomed spirited bidding for our curated selection of exceptional coloured gemstones and diamonds, fine vintage and contemporary jewellery, with a 76% increase of total registrants and 65% increase of online bidders on the previous year."