A new world record has been set for the sale of any gemstone at auction in Hong Kong where the Pink Star diamond went for more than $71m (£57m. The oval-shaped 59.6 carat stone, which is the largest polished diamond in its class to go under the hammer, was sold at Sotheby’s in five minutes, going to Hong Kong jewellery retailer Chow Tai Fook Jewellery.