World's Largest Uncut Diamond Fails to Sell at Sotheby's Auction

— -- After much admiration and anticipation, the world’s largest uncut diamond failed to sell at a public auction Wednesday night.

The 1,109 carat white diamond did not meet the reserve price, or minimum acceptable bid, which was not specified by Sotheby’s auction house in London. The rough stone was expected to fetch at least $70 million, but the bidding stopped at $61 million, Sotheby’s said.

The rock was discovered in November by the Lucara Diamond Corp. in the company's Karowe mine in north-central Botswana. It’s the largest diamond to be recovered in the southern African nation and the biggest find worldwide in over 100 years. The tennis-ball-size stone, named Lesedi la Rona (Our Light in Setswana), is thought to be 3 billion years old.

“Every aspect of tonight’s auction was unprecedented,” Sotheby’s said in a statement Wednesday evening after bidding ended. “No one alive today has ever seen a gem-quality rough diamond of this incredible scale; no rough diamond of importance has ever before been offered before at public auction; and no diamond — polished or rough — has ever been estimated at this price level.”

Lucara CEO William Lamb said in a statement that his company will retain Lesedi la Rona. Hours before the historic auction, a nervous and excited Lamb told ABC News that the “best case scenario” would be for the diamond to sell to someone who would showcase it at a museum rather than keep it in a private collection.

Hoping to share the colossal rough stone with the widest audience possible, the Canadian mining company broke with tradition by selling it at a public auction instead of inviting sealed bids from wealthy dealers in the diamond industry. Lesedi la Rona is second only to the huge 3,016.75 carat Cullinan diamond, which was mined in South Africa in 1905 and produced nine major diamonds that are among the historic Crown Jewels of the United Kingdom, according to Sotheby's.

Two independent reports commissioned by Sotheby’s found that Lesedi la Rona may have the potential to yield one of the largest top-quality diamonds ever cut and polished. The Gemological Institute of America attested to the rarity and characteristics of the stone in a letter to Sotheby’s that was published by the auction house.

“The 1,109 ct rough’s top color and transparency exemplify the ‘limpid’ appearance commonly associated with type IIa diamonds,” the Californian nonprofit gem research institute wrote, referring to a rare subgroup that accounts for fewer than 2 percent of gem diamonds. “Once polished or examined in more detail, a final answer will become clear.”

Henri Barguirdjian, the president and chief executive of Graff Diamonds, told The New York Times that each carat of the gem was worth about $62,000.