Lucara Diamond Corp has announced that its giant Lesedi la Rona gem will be retained by the company after bidding at a Sotheby’s auction in London did not meet the reserve price.
The 1,109-carat diamond was discovered by the Vancouver-based company in its Botswana mine last November.
It was expected to sell for more than $70m (£52.1m), but the highest bid reached $61m, according to Reuters.
Lucara’s share price fell 16 per cent to $3.31 on the Toronto Stock Exchange.
When the stone was found, Lucara president and chief executive William Lamb said: "The significance of the recovery of a gem quality stone larger than 1,000 carats, the largest for more than a century and the continued recovery of high quality stones from the south lobe, cannot be overstated.
"Our focus on mining the south lobe, which is delivering value beyond expectation, has been perfectly timed with the commissioning of our recent plant modifications, enabling the recovery of these large, high quality exceptional diamonds."