World's largest uncut diamond

Brexit blamed for world's largest uncut diamond failing to sell at London auction

The Lesedi La Rona, a 1,109-carat, tennis ball-sized gem found in Botswana, had been predicted to sell for over $US70 million ($90 million).

But the Sotheby's auctioneer failed to persuade bidders to go above $US61 million for the jewel, which was discovered in 2015 by the Lucara Diamond Corp.

"Though widely admired in the months preceding this evening's auction, and despite having seen bidding in the salesroom, the Lesedi la Rona failed to reach its reserve price and consequently did not find a buyer tonight," Sotheby's said in a statement later.