MajorsJul 18, 2025
Lewis Heyman on Sourcing Gemstones, Post-Retirement PlansHe retired last month after 28 years traveling the world to source the very best gemstones for his family’s jewelry business, Oscar Heyman.
SourcingApr 29, 2019
Botswana’s Karowe Mine Yields Another Huge Stone
It weighs 1,758 carats and is described as being “near-gem of variable quality.”
This 1,758-carat stone just found at the Karowe mine in Botswana weighs close to 352 grams and measures 83 mm x 62 mm x 46 mm. It is approximately as big as a “good-sized pear,” miner Lucara Diamond Corp. said.
Letlhakane, Botswana—Lucara Diamond Corp. announced last Thursday that it found a 1,758-carat piece of rough at the same mine where it recovered the 1,109-carat Lesedi La Rona.
Discovered over Easter weekend, the huge stone is still being analyzed, but Lucara described it as being “near-gem of variable quality,” meaning it is an industrial diamond with sections that could produce gem-quality stones.
The 1,758-carater is one of largest rough diamonds recovered in recent history, and the second 1,000-carat-plus stone recovered from Karowe since 2015.
The largest known gem-quality diamond in history is the Cullinan, which was found in South Africa in 1905.
There has been a larger stone recovered than the Cullinan—the 3,167-carat carbonado diamond dubbed the “Carbonado do Sergio” discovered in Brazil in 1895. Carbonado diamonds are industrial-quality stones that are opaque and believed to be found only in Brazil and the Central African Republic, Stephen E. Haggerty, a research professor at Florida International University in Miami, wrote in the summer 2017 issue of GIA’s Gems & Gemology.
Discovered over Easter weekend, the huge stone is still being analyzed, but Lucara described it as being “near-gem of variable quality,” meaning it is an industrial diamond with sections that could produce gem-quality stones.
The 1,758-carater is one of largest rough diamonds recovered in recent history, and the second 1,000-carat-plus stone recovered from Karowe since 2015.
The largest known gem-quality diamond in history is the Cullinan, which was found in South Africa in 1905.
There has been a larger stone recovered than the Cullinan—the 3,167-carat carbonado diamond dubbed the “Carbonado do Sergio” discovered in Brazil in 1895. Carbonado diamonds are industrial-quality stones that are opaque and believed to be found only in Brazil and the Central African Republic, Stephen E. Haggerty, a research professor at Florida International University in Miami, wrote in the summer 2017 issue of GIA’s Gems & Gemology.
This photo provided by Lucara Diamond Corp. shows a bit of light coming through the back of the 1,758-carat chunk of rough found at Karowe mine over Easter weekend.
Lucara recovered the huge stone using XRT (X-ray transmission) technology from Tomra Sorting Solutions, which designs and manufactures sorting equipment for the mining, food and recycling industries.
In the past, many large rough diamonds were crushed during recovery because De Beers, the main diamond miner at that time, did not have the technology to detect them and, to an extent, did not care, Gemological Institute of America Senior Analyst Russ Shor wrote in a 2016 research article.
Making money in diamond mining was about speed, he wrote, with the per-carat price differential between large (above 10 carats) and small diamonds not enough to make it worth De Beers’ while to retool its processing.
(De Beers actually was the company that discovered the kimberlite pipe at Karowe in 1969 but never commercially mined the deposit. It sold its final stake in the site to Lucara in 2010.)
RELATED CONTENT: Graff Cut This 302-Carat Diamond from Lesedi La Rona
Today, large diamonds fetch huge sums on the global market so miners are putting time and money into technology that spares them.
Tomra’s XRT is sensor-based bulk sorting that can pick out the diamonds even if they are coated, low-luminescent or Type II, the company says.
Lucara implemented XRT at Karowe in 2015 and, since that time, it said it has recovered 12 diamonds weighing 300 carats or more. Half of those dozen diamonds have been gem quality and sold for a total of more than $158 million.
This includes the 1,109-carat Lesedi La Rona, which turned up in fall 2015.
Lucara expects to keep finding large, high-quality diamonds at Karowe, noting: “Each deposit has a characteristic size distribution of diamonds … The vast majority of diamond mines have ‘fine’ distributions and host [very] few large/coarse diamonds, regardless of grade. The Karowe mine has a very coarse distribution of large diamonds, up to 5 times the world average.”
More on Sourcing
The Latest
TrendsJul 18, 2025
Piece of the Week: CCWW Designs’ Shell Charm NecklaceThe charm necklace features six nautical charms of shells and coral that founder Christina Puchi collected on Florida’s beaches.
MajorsJul 18, 2025
Plumb Club Elects New Board MembersThe organization elected its youngest vice president as it looks to draw in fresh talent.
Brought to you by
Investing in the Next Generation of Bench JewelersThe Seymour & Evelyn Holtzman Bench Scholarship from Jewelers of America returns for a second year.
TechnologyJul 18, 2025
Brad Campbell, John Liebler Join Clientbook’s Executive Team Campbell joins the company as vice president of business development while Liebler is the new vice president of operations.
Weekly QuizJul 17, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
CollectionsJul 17, 2025
2026 Winter Olympic Medal Design Symbolizes UnityThe medals feature a split-texture design highlighting the Games’ first time being hosted by two cities and the athletes’ journeys.
Supplier BulletinJul 17, 2025
The INSTORE Jewelry Show 2025: Your Holiday Preparations, All Wrapped Up! Sponsored by The INSTORE Jewelry Show 2025
Brought to you by
Jewelers of America is Headed to Las Vegas for JCK 2025The countdown is on for the JCK Las Vegas Show and JA is pulling out all the stops.
SurveysJul 17, 2025
The Most Recommended Brands in the World, According to YouGovGlobally, travel and transportation brands reigned, while in the U.S., alcoholic beverage companies and a lingerie brand took the top spots.
IndependentsJul 17, 2025
Gina Ferranti of GiGi Ferranti Jewelry Dies at 59The Brooklyn-based jewelry designer is remembered as a true artist and a rare talent.
Events & AwardsJul 17, 2025
JA to Hold Learning Workshops This FallA new slate of Learning Workshops will take place in Oklahoma, Mississippi, and Georgia.
SurveysJul 16, 2025
Signet Jewelers Falls Lower on NRF’s ‘Top 100’ Retailers ListThe middle class is changing its approach to buying jewelry and affordable luxury goods, the NRF said.
FinancialsJul 16, 2025
Richemont’s Jewelry Sales Up 7% in Q1It marks the third consecutive quarter of growth for Cartier, Van Cleef & Arpels, Buccellati, and Vhernier.
WatchesJul 16, 2025
The Top-Selling Rolex Models of the Last 15 Years, According to Bob’s Watches The reseller’s market trends report, based on its sales data, also shows exactly how much Rolex prices have jumped since 2010.
AuctionsJul 16, 2025
Christie’s To Honor Dinh Van With ExhibitionThe auction house will be hosting a retrospective paying tribute to jeweler Jean Dinh Van and his company’s 60th anniversary.
IndependentsJul 16, 2025
Clyde Duneier Ushers In Fourth GenerationJake Duneier and Danielle Duneier-Goldberg have stepped into the roles of CEO and president, respectively.
CollectionsJul 15, 2025
Boucheron’s New High Jewelry Calls Attention to Nature’s ImpermanenceThe “Impermanence” collection contemplates nature through the Japanese art of Ikebana (flower arranging) and philosophy of wabi-sabi.
MajorsJul 15, 2025
James Avery Expands to 2 More StatesThe Texas-based jewelry retailer has set up shop in Tennessee and Arizona.
Events & AwardsJul 15, 2025
Neiman Marcus Vet Joins Couture as Brand Director Eric Ford will step into the role, bringing with him decades of experience.
MajorsJul 15, 2025
Ben Bridge Jeweler Acquires Olympic ManufacturingIn addition to improved capabilities, the acquisition will allow the jeweler to offer support to other independent jewelers.
CollectionsJul 15, 2025
Guzema Debuts First Colored Gemstone JewelryThe “Celestial Blue” capsule collection campaign features Olympian Kateryna Sadurska.
MajorsJul 14, 2025
Nanis Opens First StoreThe seasonal store, located in Mykonos, Greece, offers exclusive events, personal styling, and curated experiences.
IndependentsJul 14, 2025
It’s the Summer of Love at Long’s JewelersThe New England jeweler is hosting a bridal event for the month of August.
Events & AwardsJul 11, 2025
The Edge’s Annual Conference Returns in SeptemberIts sessions will focus on inventory strategies, staff performance, retention and acquisition, emerging market trends, and more.
CollectionsJul 11, 2025
Piece of the Week: Miseno’s ‘Arco’ EarringsFor its 10th anniversary, Miseno designed the “Arco” earrings based on the Arco Felice, an arch conceptualized in A.D. 95 in Miseno, Italy.
Policies & IssuesJul 11, 2025
James Avery to Donate $1M to Texas Hill Country Relief EffortsThe jewelry company is one of several contributing to relief efforts in the region after the recent floods.
TrendsJul 11, 2025
Kelly Osbourne’s Engagement Ring Is Sweet as HoneyInspired by fiancé Sid Wilson’s nickname for her, the white and yellow diamond ring features a unique honeycomb design.
