59.60-carat Pink Star. he diamond is dazzling and so is the price. This flawless 59.60-carat gem, known as the Pink Star, is expected to go for more than £40million at auction next month. That will make the huge diamond, one of the world’s rarest and with an extraordinary depth of colour, the most valuable jewel ever to be sold. Discovered in South Africa in 1999 by mining giant De Beers, the pink gem was polished and cut over two years.