This 373.72-carat rough diamond is a chip off the biggest block of rough diamond currently known to man, the 1,109-carat Lesedi la Rona. It sold for $17.5 million last week.
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.

20170516 Lucara 182This 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.

Since it started mining at Karowe in 2012, Lucara has gotten more than $1 million for each of 145 rough diamonds.

Its biggest find remains unsold, however.

The 1,109-carat Lesedi la Rona went up for public auction at Sotheby’s but nobody met the $70 million reserve price.

At the end of 2016, Lamb told National Jeweler that the rough diamond likely would be put up for sale again in 2017 but through a sealed bid tender, perhaps, and not a public auction.

When asked about the diamond on Monday, Lamb said: “We continue to speak to a number of people within the sector regarding the sale of the stone, as well as looking at options to partner to polish the stone or even polish it without a partner … We are looking at all options and hope to make a decision soon.”

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