Like much of the American west, the story of Montana sapphires begins with the search for gold.
“Sapphires were first reported by gold prospectors in 1865 in a gravel deposit along the Missouri River that later became known as Eldorado Bar,” relates gemologist Robert Kane, president and CEO of American Sapphire Company. “Miners then found them at Dry Cottonwood Creek in 1889 and Rock Creek in 1892, but their colors were generally pale, and there was little demand for them. That changed in 1895, when gold miners discovered transparent blue sapphires at Yogo Gulch. One of the miners sent a cigar box of the pebbles to George Kunz at Tiffany & Co., who identified them as fine sapphires and purchased the lot.”
Experts have since classified the area’s sapphires into two types: Montana sapphires, which come from secondary deposits in the Missouri River area, Dry Cottonwood Creek, and Rock Creek; and Yogo sapphires, which come from hard-rock primary deposits in Yogo Gulch.
“What made Yogo sapphires so remarkable was their intense blue and violet colors and extremely high clarity,” says Jeff Hapeman, founder of Earth’s Treasury, one of the largest Montana-sapphire buyers. “The original lamprophyre lava dike that was the source of these sapphires was located and mined from 1899 to 1929, from what became known as the English mine.”
Missouri River: Bar country
The Missouri River deposits include several sapphire-bearing gravel bars, extending 14 miles along both riverbanks. The biggest is Eldorado Bar, with six active mines. There are also some small commercial mines at McCune Bar, Spokane Bar, Gruell’s Bar and French Bar.
The largest mine on Eldorado Bar belongs to Don Johnson and Robert Procop. “We get all colors, including some color-change sapphires,” says Johnson, who owns supplier Obsessed Over Gems. “Purple is the favorite, which changes to blue or green under different lighting.”
Johnson, who specializes in non-heated gems due to growing demand for natural colors, sells 99% of his production to cutting factories and hobby cutters. For rough that yields faceted stones of over 3 carats, the company obtains mine-to-market reports from the Gemological Institute of America (GIA), although its ethical considerations go further. Johnson is removing the rock tailings the gold miners have left and is restoring the shorelines to their natural state. He also grows alfalfa on some of his 406 acres — not as a side business, but to provide food for elk and deer.
“Mother Nature takes good care of me; I’m returning the favor by being a steward of the land,” he says.
The smallest of the six commercial mines on Eldorado Bar belongs to Blaze Wharton of Blaze-n-Gems. He also has a store in Helena, where he sells gravel bags straight from the trommels to tourists who want to try their luck finding gems. Sapphire tourism is popular in Montana, and his is one of several mines offering people the opportunity to sift through gravel in hopes of a big find.
Wharton’s stones come in all colors. The most popular, he says, are lavender and green-blue — the latter marketed as teal — with good clarity, in all sizes up to 50 carats. About 95% are unheated, and he sells his production both locally and overseas.
Rock Creek: Volume and variety
Rock Creek, at the western edge of Montana, is the state’s largest sapphire mine. It belongs to Canada-based Potentate Mining and covers 3,500 acres, encompassing about 90% of historically known sapphire-producing ground near the Rock Creek stream.
“The gems come in all sizes and colors, including parti-colors, with about 80% being heated to improve clarity and color,” says Warren Boyd, the company’s marketing manager. Many Rock Creek sapphires are winners of American Gem Trade Association (AGTA) Spectrum awards, he adds, including 2024’s winning cut by lapidarist John Dyer.
With production of 80 to 200 kilograms per year, Potentate sells mostly to cutters. “We held our first rough tender last December in Thailand, and it was well received, so we intend to hold them twice a year,” Boyd says.
Among the tender participants was Navneet Agarwal of Thai-based Navneet Gems & Minerals, who has seen demand increase over the last few years. While most Montana sapphires sell to Americans, 40% go to global buyers, says Agarwal, adding that all his customers favor teal and green hues.
Although Potentate’s sapphires get cleaned and sorted in the US, the miner doesn’t have a permanent office there, so it stores the gems in Canada during the winter and then sends them overseas or back to the US. How will the current US tariff policy affect business?
“Well, this is the conversation these days,” Boyd sighs. “The situation is confusing, and we are looking at different options.”
Yogo Gulch: ‘Rare, transparent and unheated’
As for Yogo Gulch, by the time the English mine closed in 1929, it had produced 2.5 million carats of sapphires in total for sale around the world. Subsequent efforts to restart activity failed due to the complexity of working the hard-rock deposits. In 1973, investor Chikara Kunisaki purchased the mine, driving a 3,000-foot-long horizontal tunnel and mining there for several years. Later, he sold purchase options to other companies, but none of them saw success, and the mine reverted back to Kunisaki.
Today, his son Ron manages Yogo Sapphire Group (YSG) and expects to restart mining this year, as well as cutting and marketing. “Yogo sapphires are in demand because they are so rare, transparent and unheated, with 95% presenting a cornflower blue, while 5% are purple,” reports the younger Kunisaki, who says it’s unusual to see faceted stones larger than 1 to 3 carats.
“We have a long waiting list for those,” says YSG sales director George Lind. He affirms that “we are now mapping the deposit and hope to start mining in the future.”
Also in Yogo Gulch is the Vortex mine, which local miners started in 1984 and which adjoins the YSG site. “We have an approved decline drift to the 400-foot level, and we hope to restart mining operations soon,” says current Vortex co-owner Don Baide, adding that the site has previously produced Yogo sapphires in excess of 3 carats.
The jewelry scene
Noting rising demand and prices, Mac’s Gems in Missoula, Montana, sells Montana sapphires in silver and gold jewelry designs to a largely US clientele. Debra McClain, who co-owns the business with her husband Dave, says teal is the favored tone, but demand is strong for all colors.
For Earth’s Treasury, a longtime client of Potentate, Montana sapphires are among the most popular stones. Demand for custom-made Montana-sapphire jewelry, especially engagement rings, is growing, according to founder Hapeman, who has won several Spectrum awards for his own lapidary efforts. Customers are looking for beautiful gems that are ethically sourced, he explains. “They are amazing treasures, and we love them.”
Storied land
In addition to the scintillating stones it produces, Montana’s Missouri River area holds rich family histories.
“The great-grandfather of one of my clients was a dredge machinist in the early 1940s at the Missouri River goldfields, [which] also produced sapphires,” relates Texas gem-cutter Kory Pettman, who specializes in Montana sapphires. “The miners and their families lived at the mining camp, and the wives collected sapphires. Their children would search the discarded gravel for any missed stones.”
Pettman’s client was the granddaughter of one of these children. “She asked me to cut some of the sapphire collection she’d inherited from her grandmother to honor her memory, and I feel fortunate to help create these family heirlooms.”
A Missouri River Montana color-change sapphire from Obsessed Over Gems that is purple in incandescent light (left) and green in sunlight (right). (Don Johnson/Obsessed Over Gems)
