Offered for sale at a public auction Wednesday evening at Sotheby’s in London, the 1,109-carat stone failed to sell when it did not meet the minimum reserve, a price that was not specified.
The bidding stopped at $61 million. A fee of about 12 percent, known as the buyer’s premium, would have been added to that price, which would have brought the total cost to about $68 million.
“If you divide it by 1,109 carats, it is about $62,000 a carat,” said Henri Barguirdjian, president and chief executive of Graff Diamonds. “That is a very high price for a rough diamond, so obviously the reserve was too high.”
The stone was discovered last fall in the Lucara mine in Botswana. Selling it at auction was an uncommon move, as such stones are normally offered to a handful of sophisticated dealers in the diamond industry.
The auction was a gamble for both Lucara and Sotheby’s on the desire among the ultrawealthy for such a totem of luxury. The financial uncertainty after Britain’s vote last week to leave the European Union may have affected the bidding interest.
In the weeks preceding the sale, potential bidders had a chance to examine the stone. Evidently they did not think that the diamond, which would most likely have been cut into smaller stones, would yield enough value to justify a higher price.
The record price for a rough stone was set in May, when Lucara sold an 813-carat diamond at a private auction for $63 million, or about $77,500 a carat.