Sourcing

11,685-Carat Emerald Recovered From Zambia’s Kagem Mine

SourcingAug 27, 2025

11,685-Carat Emerald Recovered From Zambia’s Kagem Mine

Dubbed the “Imboo,” or “buffalo,” emerald, the rough gemstone is part of Gemfields’ latest emerald auction, which is taking place now.

11,685-carat Imboo emerald
“Even under the beam of a strong light that is necessary to illuminate a gemstone of this remarkable size, ‘Imboo’ reveals an intense, verdant green with golden warmth and a clarity that captivates the eye,” said Adrian Banks, Gemfields’ managing director of product and sales. (Photo courtesy of Gemfields)
Bangkok—Kagem, the emerald mine Gemfields operates in partnership with the Zambian government, has yielded its biggest gem-quality stone yet—a 11,685-carat gemstone dubbed the “Imboo,” or “buffalo,” emerald.

Recovered Aug. 3, the gigantic gemstone is being offered in Gemfields’ latest high-quality emerald auction, which began Monday and runs to Sept. 11.

In a statement issued Tuesday, Gemfields did not provide an estimated sale price for the rough emerald, with a company spokesperson noting the miner never provides the value of individual lots offered at auction, only the auction total.

However, Gemfields Managing Director of Product and Sales Adrian Banks speculated in the statement that the Imboo could produce several fine-quality polished emeralds of “significant size.”

“Such a rare collection could form an entire high jewelry suite from this single gemstone,” he said, which is what Chopard did with the 6,225-carat “Insofu” emerald, also recovered from Kagem.

“In my 30 years at Kagem, I’ve rarely seen such a remarkable formation of large, high-quality crystals. This is a true masterpiece carved by nature’s hand.” — Jackson Mtonga, Kagem sort house 

According to Gemfields, geologist Dharanidhar Seth and Justin Banda, a veteran miner said to be “instrumental” in the extraction of many noteworthy gems, discovered the over 11,000-carat emerald in the mine’s Chama pit.

The pit is the portion of the mine that has yielded large emeralds in the past.

The Insofu was discovered there in 2010, followed by the 5,655-carat “Inkalamu” emerald in 2018, and the 7,525-carat “Chipembele” emerald in 2021.  

Gemfields said the composition of Chama is a classic example of what’s known as a triple junction, where three distinct lithological and structural domains converge. 

In the case of Kagem, which is located in Zambia’s Copperbelt Province, they are a talc-magnetite schist, or TMS, layer; a concordant quartz-tourmaline, or QT, vein; and a discordant quartz-feldspar, or QF, vein.

This setting creates ideal conditions for the formation of emerald crystals, particularly large-sized crystals, Gemfields said. 

In addition to the individual Imboo, Insofu, Inkalamu, and Chipembele emeralds, the Chama pit also produced the “Kafubu Cluster,” a group of emeralds weighing nearly 190,000 carats found in 2022.

 Related stories will be right here … 

In addition to coming from the same area of mine, the Imboo emerald shares another similar with the other large emeralds recovered from Kagem in the last 15 years—its name.

Imboo, pronounced “im-bow,” translates to “buffalo” in the local Bemba and Lamba dialects and continues Gemfields’ tradition of nodding to Zambia’s wildlife when naming exceptional emeralds, it said.

Insofu means “elephant,” while Inkalamu translates to “lion,” and Chipembele to “rhino.”

Gemfields said it named this particular stone with the buffalo’s “determination, endurance, sense of community, and, of course, its sheer size” in mind. 

African buffalos, which are divided into four distinct sub-species, are about 4-5 feet tall and can weigh anywhere from 660 to nearly 2,000 pounds, according to the African Wildlife Foundation.

“In my 30 years at Kagem, I’ve rarely seen such a remarkable formation of large, high-quality crystals,” said Jackson Mtonga, the Kagem sort house’s grading manager. 

“The immense size and nature of the crystal formation makes it fitting that this unique piece is given the name ‘buffalo,’ or ‘Imboo’ in our local languages. This is a true masterpiece carved by nature’s hand.” 

The Latest

National Jeweler columnist Peter Smith
ColumnistsSep 05, 2025
Peter Smith: A Lasting Lesson From Maurice Tempelsman

Smith recalls a bit of wisdom the industry leader, who died last week, shared at a diamond conference years ago.

Jamie Turner Victoria Labradorite Necklace
CollectionsSep 05, 2025
Piece of the Week: Jamie Turner’s ‘Victoria’ Necklace

The “Victoria” necklace features a labradorite hugged by diamond accents in 18-karat yellow gold.

Stock image of the U.S. Supreme Court
Policies & IssuesSep 05, 2025
Trump Takes Tariffs Case to the Supreme Court

Two lower courts have moved to block the import taxes, which will remain in place as the legal battle continues.

japac-btyb.png
Brought to you by
Rallying Call for the Jewelry Industry on Tariffs and Other Key Issues

Jewelers of America is leading the charge to protect the industry amidst rising economic threats.

Patrick Mahomes Hublot campaign
WatchesSep 05, 2025
Patrick Mahomes Is the New Hublot Brand Ambassador

The Kansas City Chiefs quarterback shares Hublot’s dedication to pursuing greatness, the Swiss watchmaker said.

Weekly QuizSep 04, 2025
This Week’s Quiz
Test your jewelry news knowledge by answering these questions.
Take the Quiz
gia-edu main image.png
Supplier BulletinSep 04, 2025
A Brilliant Future Is Here

Sponsored by GIA

A street in Carlsbad California
Events & AwardsSep 04, 2025
27 Can’t-Miss Converge Sessions, Events

From sunrise yoga to tariffs talks, these are some events to check out at the upcoming inaugural event.

rio-article photo-diamond.jpg
Brought to you by
Taking the Moment Head On: How Rio Grande Champions the Present & Future of Fine Jewelry

As a leading global jewelry supplier, Rio Grande is rapidly expanding and developing new solutions to meet the needs of jewelers worldwide.

Shot from Breitling new NFL campaign
WatchesSep 04, 2025
Breitling Takes Its NFL Game to the Next Level

Breitling is now the NFL’s official timepiece partner, a move that puts the brand in front of the millions of Americans who watch football.

NYC Jewelry, Antique, & Object Show Autumn 2025
Events & AwardsSep 04, 2025
The NYC Jewelry, Antique, & Object Show Returns in November

NYCJAOS is set for Nov. 21-23 in New York City’s Chelsea neighborhood.

Claire’s storefront
MajorsSep 03, 2025
These Are the Nearly 300 Claire’s Stores Set to Close

A new court filing details the locations of the stores that will close, as well as the 830 that will remain open.

Stuller’s Tools, Equipment, & Metals and Findings & Metals Catalogs
MajorsSep 03, 2025
Stuller Releases 2 New Catalogs

The new catalogs are “Tools, Equipment, & Metals” and “Findings & Metals.”

Effy Jewelry Multicolor Sapphire Bangle
TrendsSep 03, 2025
Amanda’s Style File: A Perfect Birthstone

Sapphire’s variety of colors make it the perfect birthstone for September.

Woman with hands crossed wearing jewelry
FinancialsSep 02, 2025
Lab-Grown Diamonds, Lower-Priced Fashion Jewelry Drive Signet Jewelers’ Q2 Sales

The retailer has raised its guidance after seeing total sales increase 3 percent in the second quarter, beating expectations.

Jean-Christophe Bédos Birks
MajorsSep 02, 2025
Birks CEO Jean-Christophe Bédos Steps Down

Niccolò Rossi di Montelera, executive chairman of the board, was appointed as interim CEO.

Harry Winston Ginza Flagship Exterior, Interior
MajorsSep 02, 2025
Harry Winston Opens Its Largest Flagship in Japan

The three-floor space also features the jeweler’s largest VIP salon in Japan and offers an exclusive diamond pendant.

All Hours: Stephanie Gottlieb Fine Jewelry x Oak and Luna Campaign Imagery
CollectionsSep 02, 2025
Stephanie Gottlieb Debuts Silver Designs in ‘All Hours’ Collab

The collection is a collaboration between Stephanie Gottlieb Fine Jewelry and Oak and Luna, focusing on understated essentials.

Sothebys The Desert Rose orangy pink diamond collectors week
AuctionsAug 29, 2025
Sotheby’s UAE Sale to Feature 32-Carat Fancy Vivid Orangy Pink Diamond

The highlight of a single-owner jewelry and watch collection, it’s estimated to fetch up to $7 million at auction this December.

Calvin Klein watch and jewelry campaign
FinancialsAug 29, 2025
Movado’s Q2 Sales Rebound Despite Tariff Impact

CEO Efraim Grinberg noted a resurgence in the fashion watch market.

Mark Davis Bullseye Necklace
CollectionsAug 29, 2025
Piece of the Week: Mark Davis’ ‘Bullseye’ Necklace

The “Bullseye” necklace, with vintage bakelite and peridot, August’s birthstone, is the perfect transitional piece as summer turns to fall.

Image #1_Resized.png
Supplier BulletinAug 28, 2025
Clientbook Is Helping Jewelers Turn Clienteling Challenges into Wins with Hands-On Training and Coaching

Sponsored by Clientbook

GIA’s new report for lab-grown diamonds
GradingAug 28, 2025
GIA’s New ‘Quality Assessment’ for Lab-Grown Diamonds Is Coming

It will classify lab-grown stones into one of two categories, “premium” or “standard,” in lieu of giving specific color and clarity grades.

Botswana President Duma Boko
SourcingAug 28, 2025
Botswana Declares Public Health Emergency Amid Diamond Sales Slump

President Duma Boko addressed the country’s medical supply chain crisis in a recent televised address.

Afton Robertson-Kanne Borsheims
MajorsAug 28, 2025
Borsheims Names New Jewelry Buyer

Former Free People buyer Afton Robertson-Kanne recently joined the retailer.

Sissy’s Log Cabin Back to School and Bling
IndependentsAug 28, 2025
Sissy’s Log Cabin Donates School Supplies to Memphis Students

The jeweler teamed up with two local organizations for its inaugural “Back to School and Bling” event.

Taylor Swift Engaged
EditorsAug 27, 2025
Taylor Swift’s Engagement Ring Is a Fairy Tale for Vintage Diamond Cuts

The singer’s new bling, reportedly a natural old mine-cut diamond, is no paper ring.

Shopping cart
SurveysAug 27, 2025
Consumer Confidence Slips in August Amid Job, Income Worries

Plans for dining out, booking vacations, and buying big-ticket items were down.

×

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