Christie’s sold $79.8 million (HKD 618.7 million) worth of jewelry at its Hong Kong auction, with Harry Winston purchasing the most expensive diamond. Nayla Hayek, the jeweler’s CEO, bought the rectangular-cut, 3.98-carat, fancy vivid blue, VVS2 diamond for $8.9 million, or $2.2 million per carat, Christie’s said. The price of the stone, which was mounted in a ring along with cushion- and triangular-shaped pink diamonds, fell within the pre-sale estimate of $8.3 million to $11 million.