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The 1,098-carat rough diamond discovered this month at the Kurowe Mine, owned by the Lucara Diamond Corporation.



It’s not often that that one reads about the discovery of a 1000-plus carat rough diamond, but June 2021 has proven to be an exception to the rule, and the star of the show once again is the Kurowe mine in Botswana.

Just days after Debswana, the diamond mining company owned jointly by De Beers and the government of Botswana, announced the recovery 1,098-carat stone, which it the claimed to be the third-largest gem-quality diamond ever mined, the owner of Kurowe, the Lucara Diamond Corporation, declared that it has now laid claim to the title, following the discovery of a 1,174.76-carat rough diamond at its facility.

What is more, Lucara believes that the massive stone is most probably part of what was an even larger rough diamond, most probably in excess of 2,000 carats. This is because it was found close by three also-unusually large rough stones, respectively 471 carats, 218 carats and 159 carats.

The largest rough diamond ever mined was the 3,106.75-carat Cullinan, found at what then was called the Premier Mine in South Africa in 1905, and today is called the Cullinan Mine. The second largest rough stone is generally considered to be the 1,109-carat Lesedi La Rona, which was discovered on November 16, 2015, in the South Lobe of the Karowe mine, about 200 meters below the earth’s surface.

But the Lesedi La Rona is actually the third largest rough diamond discovered, since the second largest was the 1,758-carat Sewelô diamond, also discovered at Kurowe in April 2019. It however was not gem quality, being covered by a layer of opaque black carbon and with a surface that was severely pitted. Still, it was purchased for an undisClosed amount by LVMH, which believed that the right cut will reveal a polished diamond of considerable potential.


Kurowe’s south lobe area has turned out to be a real bonanza of Lucara. The latest find is the 1,000-plus carat stone mined in the area in the past six year, credited in part to the use of a Mega Diamond Recovery circuit, during which X-ray technology is used to locate stones before they are potentially broken up during the recovery process.

In fact, during an 11-day production run this month four high-quality white diamonds weighing between 67 carats and 148 carats were recovered.  

Karowe has produced 12 diamonds greater than 100 carats since the start of the year, with eight being were larger than 200 carats. They included Two high quality stones weighing 341 carats and 378 carats, discovered in January.

Rough stones weighing more than 10.8 carats, which traditionally is a threshold of usually large diamonds,  made up 17.5 percent of the total carat weight of output at Kurowe in June, Lucara stated.

The 1,758-carat Sewelô diamond, discovered at Kurowe in April 2019.

A nighttime image of the Kurowe Mine in operation.


The new discoveries at Kurowe came at an opportune time for Lucara, which announced this month that it had sold shares in the company for $30.9 million, which would be reinvested in maintaining and developing its Botswana mine.

A syndicate of investors led by BMO Capital Markets bought shares for shares for $17.9 millionand has the the option to purchase an additional 15 percent of stock at the same price per share.

Lucara alsoentered into a private agreement with Nemesia and other investors to sell $13 million in shares under the same terms as the public offering. Both sales are subject to regulatory approval, and are expected to close on July 15, Lucara added.

Lucara has already invested $18.7 million to expand its Karowe deposit to underground mining, which will enable to mine to operate through to 2040.

The cutting and polishing of the large stones this month will be managed through a longstanding partnership Lucara has with with HB Antwerp, a Belgian manufacturer.

HB Antwerp is also involved in the polishing and setting of the Sewelô diamond for LVMH.