(FILES) This file photo taken on June 14, 2016 shows a model posing with an uncut 1109-carat diamond named 'Lesedi La Rona' at Sotheby's auction house in London. Graff diamonds have purchased the Lesedi La Rona diamond on September 26, 2017 for $53 million from the Canadian mining company Lucara Diamond. / AFP PHOTO / BEN STANSALL