Chunk That Broke Off 1,109-Carat Diamond Sells for $17M

Vancouver, British Columbia--A 373.72-carat rough diamond that once was part of the second largest piece of rough ever found sold for $17.5 million last week, Lucara Diamond Corp. reported.

The diamond was one of 15 single-stone lots offered at the diamond mining company’s first “exceptional” stone tender of the year.

Graff Diamonds purchased the stone, posting a photo of the rough on its Instagram account over the weekend.

Lucara found the 374-carat diamond in November 2015 at its Karowe mine in Botswana at the same time it discovered the record-setting, 1,111-carat diamond (now 1,109 carats) that would come to be known as Lesedi la Rona.

CEO William Lamb said that had the smaller, 374-carat piece of rough not broken off the main stone, the diamond would have weighed almost 1,500 carats. But the huge rough diamond likely would have been crushed in the company’s recovery plant, which isn’t designed to handle stones of that size.

“If the 374-carat stone was still attached to the Lesedi, the stone would have been larger in two dimensions than the largest screen (sieve) used in the plant to separate material into different sizes,” he explained. “The original stone would have been too large to pass through the screen and the whole stone would have ended up in the crusher, where it would have been broken into a lot more pieces.”

He added that Lucara is currently in the process of upgrading its plant, an upgrade called mega diamond recovery or MDR, which will address this by recovering diamonds up to 5,000 carats right at the front of the process facility.

Also recovered from that fortuitous haul was an 812.77-carat diamond that sold for $63.1 million--more than $77,000 per carat--in May 2016, setting a new world record for a rough diamond.
 
The 374-carat diamond was the top lot in the Lucara’s tender, which was 100 percent sold by lot.

The sale, which contained rough diamond ranging from 374 to 29.9 carats in size, totaled $54.8 million, or $31,010 per carat.

Lucara said there were seven diamonds that sold for more than $2 million each. Of those, three diamonds topped $4 million.

This includes the 374-carat diamond and the auction’s second highest-grossing lot, a 182.47-carat diamond that sold for $6.3 million.

This nearly 183-carat rough diamond sold for $6.3 million, or $34,475 per carat, at Lucara Diamond Corp.’s recent tender of exceptional diamonds.