Sourcing

Potentate Mining Unveils 64-Carat Montana Sapphire

SourcingFeb 05, 2019

Potentate Mining Unveils 64-Carat Montana Sapphire

The “Ponderosa Sapphire,” recovered from Rock Creek last summer, will be on display in Tucson.

20190205_Ponderosa-header.jpg
The 64.14-carat “Ponderosa Sapphire,” uncovered at Potentate Mining’s Rock Creek mine, before heating (Photo credit: Jeffrey R. Hapeman, Earth’s Treasury)

Rock Creek, Montana—Potentate Mining has unveiled a 64.14-carat sapphire recovered at its Rock Creek mine in Montana.

The mining company believes it to be the largest gem-quality sapphire to be unearthed in the U.S.

Dubbed the “Ponderosa Sapphire” to evoke images of the West and as an ode to the ponderosa pines on the mine’s property, the gem was uncovered in August 2018 as Potentate was moving gravel to create new settling ponds for a processing plant that is in the works, the company’s marketing director Warren Boyd told National Jeweler.

The company said the rare crystal is perfectly formed and without damage because of the millions of years spent in the weathered gravels at the mine.

RELATED CONTENT: Postcard Montana: Heading West to See a Sapphire Mine
Boyd said it shows a yellow core common to Rock Creek sapphires.

If cut, the crystal would result in several large polished sapphires—due to a crack inclusion preventing one large faceted stone—but Boyd said the company isn’t in a rush to get rid of it and is likely to maintain ownership for the time being.


These shots show the Ponderosa Sapphire after heat treatment. (Photo credit: Jeffrey R. Hapeman, Earth’s Treasury)

In fact, it wants to celebrate and share the sizeable rough.

It will do that by sending the sapphire to Tucson, where the stone will be exhibited at The Collector’s Edge Minerals booth at the upcoming Tucson Gem & Mineral Show, running from Feb. 14 to 17 at the Convention Center.
Brecken Branstratoris the senior editor, gemstones at National Jeweler, covering sourcing, pricing and other developments in the colored stone sector.

The Latest

Rough montana sapphire
EditorsSep 12, 2025
Out & About: Mining Sapphires in Rock Creek, Montana

Associate Editor Lauren McLemore headed out West for a visit to Potentate Mining’s operation hosted by gemstone wholesaler Parlé Gems.

Arunashi Fordite and Rhodolite Earrings
TrendsSep 12, 2025
Piece of the Week: Arunashi’s Fordite and Rhodolite Earrings

Fordite is a man-made material created from the layers of dried enamel paint that dripped onto the floors of automotive factories.

Susan Jacques and Al Gilbertson
Events & AwardsSep 12, 2025
Al Gilbertson Wins 2025 Robert M. Shipley Award

Gilbertson has worked as a researcher, jeweler, lapidary artist, appraiser, and business owner throughout his decades in the industry.

reDollar-fine-jewelry-department.jpg
Brought to you by
reDollar.com Is Rolling Out the Next Level Jewelry, Diamond & Watch Consignment Program

With their unmatched services and low fees, reDollar.com is challenging some big names in the online consignment world.

Supreme Court stock image
Policies & IssuesSep 11, 2025
Supreme Court to Hear Tariffs Case in November

A decision likely won’t come until January 2026 at the earliest, and the tariffs remain in effect until then.

Weekly QuizSep 12, 2025
This Week’s Quiz
Test your jewelry news knowledge by answering these questions.
Take the Quiz
Tabayer’s Nordstrom Shop-in-Shop
MajorsSep 11, 2025
Tabayer Opens Nordstrom Shop-In-Shop

Located in the revamped jewelry hall at the retailer’s New York City flagship, this opening is Tabayer’s first shop-in-shop.

Gold jewelry on a scale
MajorsSep 10, 2025
Stuller to Swap Gold Scrap for Full Credit to Account

As the gold price rises, the manufacturer is offering a 100 percent payout through Sept. 30 for gold clean scrap.

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.

Tiffany & Co Favrile Beetle Necklace in Frankenstein
TrendsSep 10, 2025
Tiffany & Co. Archival Jewels Bring Life to ‘Frankenstein’

Guillermo del Toro’s 2025 “Frankenstein” will feature 27 jewels and objects from the storied brand, including pieces from its archives.

24 Karat Club banquet
MajorsSep 10, 2025
24 Karat Club of New York’s Banquet to Return to Waldorf Astoria

The Waldorf Astoria New York’s grand reopening this past summer means a homecoming for the industry group’s annual event.

Anglo American’s Quellaveco copper mine in Peru
SourcingSep 09, 2025
Anglo American to Merge With Canadian Copper Miner

Anglo plans to merge with Teck Resources Ltd. to form Anglo Teck. The deal changes nothing about its plans to offload De Beers.

The Mellon Blue diamond
AuctionsSep 09, 2025
‘The Mellon Blue’ to Return to Auction, This Time at Christie’s

The 9.51-carat fancy vivid blue diamond, which set two world auction records at Sotheby’s in 2014, is estimated to fetch up to $30 million.

Dianne Batista Phillips Auctions
AuctionsSep 09, 2025
Phillips Names Dianne Batista Head of Jewels, New York

The industry veteran joins the auction house as it looks to solidify its footprint in the jewelry market.

Anastacia Lauren, Elle Jerge, Logan Nye
MajorsSep 09, 2025
MJSA Education Foundation Announces 2025 Scholarship Winners

The nonprofit awarded four students pursuing a professional career in jewelry making and design with $2,250 each.

Korman jewelry store Austin
IndependentsSep 08, 2025
Take a Look Inside the New Korman Store in Austin

The Texas-based jeweler has also undergone a brand refresh, debuting a new website and logo.

Logos for Manufacturing Jewelers & Suppliers of America and Jewelers of America
MajorsSep 08, 2025
MJSA Is Officially Now Under JA’s Umbrella

The two organizations have finalized and signed the affiliation agreement announced in May.

Sothebys JAR and Suzanne Belperron jewels
AuctionsSep 08, 2025
Sotheby’s To Auction ‘Exceptional’ Collection of JAR, Suzanne Belperron Jewels

The single-owner sale will headline Sotheby's inaugural jewelry auction at the Breuer building, its new global headquarters, this December.

A street in Carlsbad California
Events & AwardsSep 08, 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.

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.

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.

gia-edu main image.png
Supplier BulletinSep 04, 2025
A Brilliant Future Is Here

Sponsored by GIA

Lucara pink diamond
SourcingSep 04, 2025
Lucara Unveils Unusual 37-Carat Pink Diamond

The Type IIa stone, recovered from Botswana’s Karowe diamond mine last month, features unique coloration.

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.

Fabergé x Gemfields Malaika Egg
SourcingSep 03, 2025
Gemfields Confirms Completion of Fabergé Sale

U.S.-based investment company SMG Capital LLC is the new owner of the luxury brand.

×

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