First Diamonds from Sierra Leone’s Tongo Mine Coming to Market
Australian company Newfield Resources is developing the mine and will sell its production through Bonas Group in Antwerp.

Newfield Resources Ltd., the company developing the mine, announced in late April it had inked an exclusive diamond sales and marketing agreement with Bonas for the mine’s production.
Via its partnership with Bonas, Tongo goods will be tracked from mine to market using Sarine Technologies’ traceability program, Newfield said.
The mine, which has been in the works for more than decade, is “well known for its high-quality material,” Bonas said.
Tender viewings of the Tongo material will take place on the first floor of the Bonas Group offices in Antwerp between May 16 and 20.
The sale is scheduled to close May 20 at 1 p.m. CET/7 a.m. EDT and will be an online, highest bid tender on Newfieldbids.com.
Bookings for the tender are invitation-only, but requests can be submitted to Bonas Antwerp. Interested clients are requested to call the office at +32 (0) 3233 7080.
Based in Australia, Newfield has been developing the Tongo Diamond Project since 2018, when it acquired the site from Stellar Diamonds.
The project comprises two adjacent mining licenses covering a combined area of 134 square kilometers (about 52 square miles) in eastern Sierra Leone with five primary kimberlite pipes.
The first two pipes Newfield will mine have been dubbed Kundu and Lando.
Newfield said processing from the underground and surface at Kundu continues to yield “encouraging results,” with a high proportion of what’s recovered turning out to be gem-quality diamonds.
It is believed Tongo will produce 8.3 million carats of diamonds over the span of its life, including an indicated and inferred resource of 3.03 million carats at Lando and 2.76 million carats at Kundu.
Newfield employed 200 people at the mine as of March 31, including graduate trainees, contractors, and interns. Of the 200, 166 (83 percent) are local Sierra Leonians and 128 (64 percent) have permanent employment contracts, it said.
Twelve percent (about 20 people) of the local employees are women. Newfield said it intends to increase the number of women working at the mine, in line with its diversity policy.
In addition to Tongo in Sierra Leone, Newfield is conducting diamond exploration in neighboring Liberia via two licenses covering 670 square kilometers (about 259 square miles), known collectively as the Kumgbo Kimberlite Project.
The Latest

A ring set with “hogback” diamonds, an early stone cut dating to around the 16th century, sold for more than $20,000 at a U.K. auction.

The rainbow version of the ring, our Piece of the Week, features angel-cut, octahedral lab-grown sapphires designed to be worn as armor.

The new initiative donates a portion of the proceeds from select charms to charitable causes.

Colored gemstones, artisan finishes, mixed metals, and meaningful details are shaping demand in bridal jewelry.

The Brooklyn-based jeweler created a limited-edition version of its “Aura” eternity band, set with gemstones in the team’s colors.


Senior Editor Lenore Fedow headed to Savannah to learn more about the 10-year, $10 million partnership between JM and the art school.

Its new capsule jewelry collection features gold-finished stainless steel pieces designed for a maximalist look without a luxury price tag.

DCA is preparing the next generation of professionals by supporting workforce development, leadership growth, and career advancement.

The week-long event in Geneva is slated for April 2027.

Jewelers are missing out by not offering this one key add-on at the online point of sale, Emmanuel Raheb writes.

The fourth collaborative collection from the retailer and jewelry content creator focuses on gemstone charms and strands of colorful beads.

This year’s AGTA Spectrum & Cutting Edge Awards will feature two new categories.

The collection features traceable alexandrite from Brazil in calibrated sizes that is sorted by grade.

Dhaval Raja has been appointed to the role.

The capsule collection looks to vintage trunk pins that echo the spirit of speed, freedom, and the mythology of the American road trip.

SSEF issued a notice about the potential new source of the sought-after gemstone, citing “credible reports” from trade sources.

As Amazon Prime Day kicks off, Etsy is encouraging shoppers to support small businesses.

Cole Winward is the recipient of 2026 AGA Gemological Scholarship.

Whether they evoked nostalgia, wonder, or laughter, these jewels put a smile on our faces.

Scheduled for April 2027, Basilia will be the first watch and jewelry trade show held in Basel since the collapse of Baselworld in 2020.

Submissions for the milestone 25th annual Gem Awards will be accepted across three categories from now through July 31.

The beloved beagle dons his aviator outfit for the new Engineer Master II Snoopy Flying Ace timepiece.

The recent high jewelry auction, which also featured the sale of a 10-carat blue diamond, was “a celebration of color.”

She wore the “Le Cauri Endiamanté” earrings, our Piece of the Week, in the Obamas’ first dual portrait for the Obama Presidential Center.

Couture’s Michelle Orman joins Amanda Gizzi and Michelle Graff for this special post-Market Week episode of My Next Question.

The lab is seeing emeralds with filler added post-testing enter the market, accompanied by reports that indicate little to no treatment.

The third generation of the Stern family to head Patek Philippe, he navigated the “quartz crisis” and preserved the brand’s independence.

























