Lucara just uncovered this 1,174.76-carat rough stone from its Karowe diamond mine in Botswana, marking the third weighing more than 1,000 carats to be recovered from mine’s South Lobe since 2015.
Vancouver, Canada—There’s been another big diamond find.
This time, diamond miner Lucara recovered a 1,174.76-carat rough stone from its Karowe diamond mine in Botswana.
Measuring 77 mm x 55 mm x 33 mm, the gem is described as clivage—lower quality rough that needs to be split before being processed further—of variable quality with “significant domains” of high-quality white gem material, according to the miner.
The rough was uncovered from the direct milling of ore sources from the EM/PK(S) unit of the South Lobe.
Lucara said on the same production day, several other diamonds of similar appearance were recovered from the same circuit—weighing 471 carats, 218 carats, and 159 carats—indicating the large rough was part of a bigger diamond with an estimated weight of more than 2,000 carats.
Lucara also found these diamonds in the same production run as the 1,174-carat rough diamond in Botswana.
Meanwhile, the 11-day production run of EM/PK(S) in June that sourced the 1,174-carat stone also turned up several high-quality rough white gemstones: a 148-carat rough, a 90-carat rough, an 88-carat rough, an 86-carat rough, and a 67-carat rough.
“Lucara is delighted to be reporting another historic diamond recovery and its third diamond over 1,000 carats, a world record for Karowe,” CEO Eira Thomas said.
“Although complex, these diamond recoveries do contain large domains of top color white gem that will be transformed through our partnership with HB Antwerp into valuable collections of top color polished diamonds, very much in high demand in the market today.”
The 1,174-carat diamond is the third weighing more than 1,000 carats that has been recovered from Karowe’s South Lobe since 2015, including the 1,758-carat Sewelô and the 1,109-carat Lesedi La Rona, though the latter was gem-quality rough compared with variable quality for the other two.
Joining Lesedi la Rona in the notable gem-quality diamonds finds of late is the recent 1,098-carat recovery from Debswana, considered to be the third largest on record.
As these numbers show, big diamond finds have become more common in the past handful of years.
This is due largely to an improvement in the technology behind processing and recovering diamonds, spurred along by a demand for larger stones, industry expert Russell Shor wrote in a 2016 Gems & Gemology article.
Advances, he wrote, include in the initial crushing—“‘kinder, gentler’ methods known as ‘autogenous,’ which tumbles or grinds the kimberlite pieces against one another without the intense pressure generated by crushing”—as well as the use of X-ray processing, which improved the recovery rate and saved large stones before they hit the crushers.
