NEW YORK, NY (REUTERS).- A more than 10 carat purplish-pink diamond expected to fetch up to $15 million failed to sell at Christie’s Magnificent Jewels auction on Tuesday which took in a total of $31.8 million. “We were disappointed that the 10-carat purple-pink diamond did not find a buyer, (but) top-quality white, blue, pink and yellow diamonds fared very well,” said Christie’s head of jewellery in New York, Radul Kadakia. He added that a Fancy Vivid blue diamond sold for $3.67 million, or more than $1 million per carat which exceeded it high estimate. Five jewels topped the $1 million mark. Christie’s said the sale saw heavy competition among both trade buyers and private collectors for colourless diamonds, large gemstones and signed jewels. But the 10.09 carat Fancy Vivid cushion-cut was expected to be the sale’s highlight, with prices for large pink diamonds, the most expensive coloured diamonds on the market, having sk