The Canadian firm that cannot stop finding huge diamonds has found another huge diamond. This week, Lucara, the mining company led by Eira Thomas, whom I profiled recently in the magazine, announced the discovery of a five-hundred-and-forty-nine-carat ice-white stone at its Botswanan mine, Karowe. It’s the fourth-heaviest diamond ever recovered at Karowe, and maybe the prettiest. The find will only add to Lucara’s lustre. Karowe has been in operation for just seven years, but it has already found three of the ten largest rough diamonds in history.
Lucara has been both lucky and ingenious. The Karowe deposit clearly contains exceptional stones, but the firm has also been innovative in how it recovers diamonds. Lucara has pioneered the use of X-ray transmission technology, known as XRT, which scans objects for a specific atomic signature rather than for a physical characteristic, such as luminescence or weight. The engineer who works with Lucara told me that an XRT machine functions much “like an airport baggage scanner.” The scanning technology reduces the chance that miners will damage diamonds while trying to discover them. To find tiny diamonds among thousands of tons of ore, you need to crush big rocks, and the violence can damage valuable gems. The XRT machines allow Lucara to recover more large diamonds unbroken, because the ore does not need to be crushed so many times before it is sorted.
The new diamond’s discovery has pleased Lucara’s leadership team for reasons other than its beauty and potential value. In 2017, the firm installed a unit called the Mega Diamond Recovery, which was placed near the beginning of the processing circuit—the string of conveyor belts and mechanisms that leads the ore to the diamond-sorting house. The M.D.R. was designed to spy diamonds that had been liberated before the most aggressive section of the circuit—the mill—went to work, and to stop them from being damaged. Until now, the M.D.R. had not recovered a single large, valuable diamond, because most of the gems were freed later, in the mill. This single discovery will repay Lucara’s investment in the M.D.R.
The natural question is: What is the diamond worth? When I spoke to Lucara employees this week, not many people had yet seen the new stone. Those who had were bowled over. Lucara’s sales manager in Botswana, Stephen Kgobe, a keen distance runner who is by nature taciturn and not prone to hyperbole, texted me to say, “The stone is marvelous and is the masterpiece of its kind . . . smooth surface and the purity is fantastic.” Both John Armstrong, Lucara’s leading geologist, and Eira Thomas, meanwhile, described the stone to me using the same phrase: “She’s a beauty.”
Although the new find is only around a third as large as the enigmatic, black-covered diamond that was discovered in April of last year—which is now known as Sewelô and is partly owned by Louis Vuitton—the five-hundred-and-forty-nine-carat stone is almost certainly worth much more. Rough-diamond prices are subjective but are governed by color, clarity, and weight. Berenberg investment bank estimated that the diamond might sell for between fifteen and twenty million dollars, but this estimation seemed low, based on the sale of previous exceptional large stones.
Armstrong told me that the new diamond’s color and quality could certainly be compared to the Queen of Kalahari, a beautiful three-hundred-and-forty-two-carat stone that was recovered in 2015 at Karowe and later sold for $20.55 million to an unidentified buyer. (It was eventually bought by the jeweller Chopard for an undisclosed sum.) Armstrong also compared the new stone to the Constellation, a pristine eight-hundred-and-thirteen-carat stone also recovered at Karowe in 2015. The Constellation sold for $63.1 million, or $77,613 per carat—the highest price ever paid for a rough diamond. If the new five-hundred-and-forty-nine-carat diamond approached the Constellation’s price-per-carat valuation, its price could exceed forty million dollars. (Lucara did not comment on the stone’s potential value.)
There is also the question of how Lucara plans to sell the new diamond. Traditionally, miners have sold their stones to the diamantaire market at tenders and then have taken no further interest in what happens to the diamond. Eira Thomas has rethought her firm’s role in the sales process. With Sewelô, the large black diamond now partly owned by Louis Vuitton, Lucara still owns a fifty-per-cent stake, because Thomas wants to participate in the “story” of the stone, and also to reap a cut of the profits once the stone is polished. I asked Armstrong what Lucara planned to do with the five-hundred-and-forty-nine-carat diamond, but he said that it was too early to tell. “We have to wrap our heads around what it is, first,” he said.
Whatever the stone eventually sells for, and however it reaches its buyer, its discovery is cause for celebration—and not only for Lucara. As I learned during my recent trip to Botswana, the country has managed revenues from its natural resources admirably. The government raises hefty taxes and royalties from diamond producers. Much of that money is spent on schools, scholarships, infrastructure, and health-care projects. Keith Jefferis, an economist and a former deputy governor of the Bank of Botswana, told me that diamond revenues had lifted hundreds of thousands of Botswanans out of poverty since the country became independent, in 1966.“The contribution of diamonds has been immense,” Jefferis said. “It’s really underpinned the transformation of what was a very poor country to an upper-middle-income country.”
The new diamond was recovered on Sunday, February 2nd. By a strange quirk of fate, Thomas and Armstrong were visiting the Karowe mine at the end of January from their new headquarters in London. For a while, on January 31st, Thomas and Armstrong stood at the bottom of the vast pit in hard hats and fluorescent vests, watching diggers load ore from a section of the deposit called EM/PK(S)—a section from which the majority of the firm’s most valuable diamonds have emerged. (One Lucara geologist described EM/PK(S) as the mine’s “G-spot.”) Two days later, material from that section was travelling through the M.D.R. when the five-hundred-and-forty-nine-carat diamond was discovered. It struck Armstrong that he might have unwittingly watched as the material carrying the big diamond was mined. “We were there,” Armstrong told me. “That’s pretty cool.”
