Sourcing

Botswana’s Karowe Mine Yields Another Huge Stone

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.”

20190429_1758_header.jpg
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.

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.
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.”
Michelle Graffis the editor-in-chief at National Jeweler, directing the publication’s coverage both online and in print.

The Latest

Saks on Amazon flagship window
MajorsMay 16, 2025
Saks Fifth Avenue, Amazon Partner on Luxury Online Storefront

Plus, parent company Saks Global announces plans to cut ties with up to 600 vendors.

Graphic for My Next Question webinar with guest Peter Smith
Recorded WebinarsMay 16, 2025
Watch: Physical Retail Is Not Dead

Peter Smith joined Michelle Graff to chat about the state of brick-and-mortar stores and share a few book and podcast recommendations.

Tejen Candy Bowl Torque Necklace
CollectionsMay 16, 2025
Piece of the Week: Tejen’s ‘Candy Bowl’ Torque Necklace

The necklace features a candy-colored Australian white opal in 18-karat Fairmined gold, as the brand was named a Fairmined ambassador.

antique_Vegas_2024_by_headshot_stories_9454.jpg
Brought to you by
Las Vegas Antique Jewelry & Watch Show: Showcasing the Most Collectible Merchandise from Across the Globe

Gain access to the most exclusive and coveted antique pieces from trusted dealers during Las Vegas Jewelry Week.

1 Camilla Dietz Bergeron.jpg
Supplier BulletinMay 15, 2025
Treasure Hunting at the Las Vegas Antique Jewelry and Watch Show

Sponsored by the Las Vegas Antique Jewelry and Watch Show

Weekly QuizMay 15, 2025
This Week’s Quiz
Test your jewelry news knowledge by answering these questions.
Take the Quiz
The Mediterranean Blue diamond
AuctionsMay 15, 2025
'The Mediterranean Blue' Diamond Sells for $21M at Sotheby’s

A private American collector purchased the 10-carat fancy vivid blue diamond.

Jessica McCormack Fruit Salad Campaign Imagery
CollectionsMay 15, 2025
Jessica McCormack’s ‘Fruit Salad’ Collection Is Fresh for Summer

The designer has taken the appeal of freshly picked fruit and channeled it into a capsule collection of earrings, necklaces, and pendants.

Supplier Spotlight -Recorded-Webinar.png
Brought to you by
Watch: The Winston Red: GIA Examines the Smithsonian’s Newest Addition

Supplier Spotlight Sponsored by GIA

Disability advocate Catarina Rivera, JVC ADA compliance guide, circle of hands wearing jewelry
Policies & IssuesMay 15, 2025
State of Retail: How to Better Serve Customers With Disabilities

Around 54 million Americans and counting live with a disability. Here’s how to make your jewelry store and website more accessible.

Sekou Andrews
Events & AwardsMay 15, 2025
Poet Sekou Andrews to Give Closing Keynote at Converge

The event is also accepting poster submissions now through June 16.

Pope Francis
Policies & IssuesMay 14, 2025
Here’s What Happened to Pope Francis’ Ring

Before Pope Leo XIV was elected, a centuries-old procedure regarding the late pontiff’s ring was followed.

1998 Cosmograph Daytona, Ref.16516 Rolex
AuctionsMay 14, 2025
Custom Rolex Pulled From Sotheby’s Sale

The one-of-a-kind platinum Rolex Cosmograph Daytona was estimated to fetch up to $1.7 million.

Jeweler Constance Polamalu at Bloomstone, a store that specializes in lab-grown diamonds
Lab-GrownMay 14, 2025
State of Diamonds: What’s Next for Lab-Grown Diamonds?

While the product has entrenched itself in the market, retailers and consultants are assessing the next phase of the category’s development.

Surveillance footage Tiffany & Co. Seattle robbery
CrimeMay 14, 2025
Seattle Detectives Seek Public’s Help in Tiffany & Co. Robberies

The police are trying to identify the man suspected of robbing two Tiffany & Co. locations in the area.

Jeff Corey, new chairperson of the board for the Jewelers Board of Trade
MajorsMay 14, 2025
Jeff Corey Elected Chair of JBT Board

The well-known Maine jeweler takes over for Brian Fleming and will serve a one-year term.

Foundrae Ingot Pendant
Policies & IssuesMay 14, 2025
Foundrae Donates $11K to Ethical Metalsmiths

The donation was the result of the brand’s annual Earth Day Ingot event.

Eiseman Jewels ribbon cutting ceremony
IndependentsMay 13, 2025
Eiseman Jewels’ Renovated Dallas Store Is Bigger and Better

Located in NorthPark Center, the revamped store is nearly 2,000 square feet larger and includes the first Tudor boutique in Dallas.

Diamond Council of America
MajorsMay 13, 2025
DCA Announces New Learning Platform, Course Updates

The nonprofit has made updates to the content in its beginner and advanced jewelry sales courses.

Malyia McNaughton and Elyssa Jenkins-Pérez
MajorsMay 13, 2025
BIJC Launches New Education Fund

BIJC President Malyia McNaughton will shift roles to lead the new foundation, and Elyssa Jenkins-Pérez will succeed her as president.

Harwell Godfrey Snake Giza Ring, Foundrae Mind, Body Soul Story Necklace, Tiffany & Co. Tiffany Titan By Pharrell Williams Bracelet
TrendsMay 13, 2025
State of Jewelry Design: The Top 10 Jewelry Trends of the Past Decade

As a nod to the theme of JCK Las Vegas 2025, “Decades,” National Jeweler took a look back at the top 10 jewelry trends of the past 10 years.

Lightbox’s Reminiscence Poet earrings in 14-karat white gold with lab-grown diamonds
Lab-GrownMay 12, 2025
Lightbox to Go Dark by Summer, De Beers Says

The company plans to halt all consumer-facing activity this summer, while Lightbox factory operations will cease by the end of the year.

Stock image of shipping containers
Policies & IssuesMay 12, 2025
Tariffs on Chinese Imports Temporarily Slashed as U.S.-China Reach Deal

Following weekend negotiations, the tax on Chinese goods imported into the United States will drop by 115 percent for the next 90 days.

Artists’ Jewelry: From Cubism to Pop, the Diane Venet Collection
Events & AwardsMay 12, 2025
Jewelry By Picasso, Dalí on Display at Florida Art Museum

“Artists’ Jewelry: From Cubism to Pop, the Diane Venet Collection” is on view at the Norton Museum of Art through October.

2025 CASE Award Submission Graphic
Events & AwardsMay 12, 2025
CASE Awards Now Accepting Entries For 2025

The deadline to submit is June 16.

Lugano Diamonds store in Greenwich, Connecticut
IndependentsMay 09, 2025
Lugano Diamonds CEO Resigns Amid Internal Investigation

Moti Ferder stepped down Wednesday and will not receive any severance pay, parent company Compass Diversified said.

Coeur Percé Scapular Necklace and Love Baby Locket
CollectionsMay 09, 2025
Pieces of the Week: Marie Lichtenberg’s Collaborations for Mother’s Day

Lichtenberg partnered with luxury platform Mytheresa on two designs honoring the connection between mothers and daughters.

Stock image of a man’s hands in handcuffs
CrimeMay 08, 2025
Former NYC Jewelry Store Employee Arrested in 2017 Choking Death of Boss

Michel Desalles allegedly murdered Omid Gholian inside World of Gold N Diamond using zip ties and then fled the country.

×

This site uses cookies to give you the best online experience. By continuing to use & browse this site, we assume you agree to our Privacy Policy