Vancouver, B.C.--Lucara Diamond Corp. President and CEO William Lamb knew that it was either very good or very bad news when his phone rang at 1:28 a.m. Monday morning Vancouver time.

Lucara President and CEO William Lamb said the 1,111-carat diamond workers found Monday at the company’s Karowe Mine is “slightly smaller than a tennis ball.”It turned out to be the former, as he learned that workers at the company’s Karowe Mine in Botswana had recovered a “magnificent” stone: a 1,111-carat Type IIa diamond that goes down in the record books as the second-largest gem-quality diamond ever found.

Only the 3,106-carat Cullinan Diamond, which was discovered in January 1905 at the Premier mine in South Africa and later cleaved by Joseph Asscher, is bigger.

Workers recovered the stone from materials that originated in the mine’s south lobe, an area that has yielded three 300-carat-plus rough diamonds this year, including a 342-carat stone that Lucara sold in July for $20.5 million.

Still, when that call came in Monday, Lamb was “very, very surprised,” he told National Jeweler in an interview Thursday morning. 

While he isn’t shocked by the recovery of 300-, 400- or even 500-carat stones from the mine anymore, a 1,000-carat diamond is something differently entirely. “A thousand carats … I think it would be a surprise for anybody,” he said.

The diamond, which measures 65 mm x 56 mm x 40 mm, is too large to fit in any of the rough evaluation machines Lucara has on-site in Botswana and likely will be sent to Antwerp for further evaluation. Lamb, who has not yet seen the stone in person, said what he knows from his employees on the ground in Botswana is that the diamond is a Type IIa and likely is “top color,” meaning D, E or F, and high clarity as well.

He said it is “almost impossible” at this point to estimate a sale price for the stone, or what it could yield in terms of polished diamonds.

Gem Diamonds sold a 603-carat diamond, the “Lesotho Promise,” for $12.4 million in 2006, and Petra Diamonds got $35.3 million for a 507-carat diamond in 2010.

But this diamond is much bigger, Lamb pointed out, and has added historical value as the world’s second-largest diamond behind the Cullinan. It is also the largest diamond ever found in Botswana and the largest ever recovered through a modern processing facility.

Lucara, which accounts for only 0.83 percent of global diamond production but is responsible for a high percentage of the big diamond discoveries these days, found the 1,111-carat stone using its newly installed Large Diamond Recovery (LDR) XRT machines. The machines scan pre-cleaned material recovered from diamond mines for large chunks of carbon.

Also this week, the Vancouver-based mining company found another incredible diamond, an 813-carater discovered late Tuesday.

Lamb said more information on that diamond will be available next week.

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