Second-biggest diamond ever found in Botswana mine

By Paul-Alain Hunt and Thomas Biesheuvel

A massive 2,492-carat diamond — the second-largest stone ever unearthed — has been recovered from a mine in Botswana.

The stone, found at the Karowe mine that’s run by Canada’s Lucara Diamond Corp., is yet to be thoroughly assessed and it’s unclear whether it will yield the highest-quality gems. But it’s not that much smaller than the 3,106-carat Cullinan Diamond, the world’s largest, which was discovered in South Africa almost 120 years ago.

Lucara’s Karowe mine is famous for giant stones. In 2015, Lucara found the 1,109-carat Lesedi La Rona, which at the time was the second-largest ever and eventually sold for $53 million. The mine has also yielded an 813-carat stone that fetched a record $63 million. Those two gems were both Type-IIa, the most prized stone.

The miner also previously recovered the 1,758-carat Sewelo at Karowe, but that was not a gem quality stone.

Even if the diamond does not turn out to be gem quality, recovering such a big stone will be a major boost for Lucara. The find was made using x-ray technology installed at the mine to identify high-value stones in the primary ore body.

That shows Karowe’s plant can process and detect huge gems without breaking them, a consistent headache when trying to separate brittle stones from hundreds of tons of waste rock.

“The ability to recover such a massive, high-quality stone intact demonstrates the effectiveness of our approach to diamond recovery,” Lucara Chief Executive Officer William Lamb said in the statement.

The biggest diamond ever discovered is the Cullinan, found near Pretoria in South Africa in 1905. It was cut into several polished gems, the two largest of which — the Great Star of Africa and the Lesser Star of Africa — are set in the Crown Jewels of Britain.

Lucara’s discovery comes amid a collapse in diamond prices as the industry faces headwinds in nearly all its major markets. That has been compounded by too much supply and growing erosion in some categories from synthetic stones.