AuctionsFeb 03, 2021
Buyers Went Crazy for Hester Diamond’s Mineral CollectionEditorsMar 25, 2021
5 Things to Know About … Rhodochrosite
Learn about one relatively new project bringing more material from a storied site.
A rhodochrosite mineral specimen from the Zacks pocket at the Detroit City Portal in Colorado (Photo courtesy of Collector’s Edge Minerals Inc.)
I am a gemstone lover, no question. But over the past few years, I’ve also really come to appreciate a good mineral specimen.
There’s something about specimens that crystallize in perfect cubic shapes that is so alluring, especially when they’re in matrix. This is probably where my interest in rhodochrosite grew from.
In its purest (and best, in my opinion) form, the manganese carbonate is a vibrant red color, and the fine mineral specimens are stunning.
The rhodochrosite market has plenty of interest for faceted or polished goods and mineral specimens, though both are rare. With some new activity in the space, this interest is likely to continue.
Here are five things you should know about the mineral.
1. Its looks can take a few different forms.
Rhodochrosite gets its color from manganese, but because the mineral has a variable chemical composition, the manganese can be replaced in small amounts by iron, magnesium and/or calcium.
These substitutions alter the specific gravity, hardness, and color of the mineral.
In fact, its color can range from light pink to bright red, and can even become grayish, yellowish, or brownish as the chemical composition varies.
Additionally, the environment during rhodochrosite’s formation can have a major effect on the way it looks.
There’s something about specimens that crystallize in perfect cubic shapes that is so alluring, especially when they’re in matrix. This is probably where my interest in rhodochrosite grew from.
In its purest (and best, in my opinion) form, the manganese carbonate is a vibrant red color, and the fine mineral specimens are stunning.
The rhodochrosite market has plenty of interest for faceted or polished goods and mineral specimens, though both are rare. With some new activity in the space, this interest is likely to continue.
Here are five things you should know about the mineral.
1. Its looks can take a few different forms.
Rhodochrosite gets its color from manganese, but because the mineral has a variable chemical composition, the manganese can be replaced in small amounts by iron, magnesium and/or calcium.
These substitutions alter the specific gravity, hardness, and color of the mineral.
In fact, its color can range from light pink to bright red, and can even become grayish, yellowish, or brownish as the chemical composition varies.
Additionally, the environment during rhodochrosite’s formation can have a major effect on the way it looks.
A selection of faceted rhodochrosite gemstones from the Detroit City Portal in Colorado (Photo courtesy of Iteco Inc.)
A large rhodochrosite crystal (Photo courtesy of Collector’s Edge Minerals Inc.)
Rough rhodochrosite for faceting (Photo courtesy of Collector’s Edge Minerals Inc.)
When it forms along mineral veins in pockets, rhodochrosite crystals can take shape.
It can also form as stalactites when water drips from manganese-rich rocks, creating banded material; that is often cut as slabs or used for ornamental objects, cabochons, beads, and more.
2. It’s found at a handful of sources, but supply of fine goods is low.
The list of sources for rhodochrosite doesn’t seem insignificant when you line them up, especially when compared to some other gemstones.
But the reality is that, like most colored gems, supply is limited.
“Rhodochrosite was the first stone in my cutting career where I realized you should buy things when they’re available and not when you need them. Because when you need them, they won’t be available,” gemstone cutter and wholesaler John Bradshaw said in a recent interview.
Rhodochrosite used for lapidary and mineral specimens has been found in Argentina, South Africa, Peru, Montana, Russia, China, Gabon, Mexico, and Japan, among others, according to several gemological and geological sources.
Argentina is a large source of the banded material, where stalagmites form in long-abandoned Incan silver mines, the International Gem Society said. (The mineral is often associated with silver deposits.)
The material from South Africa, meanwhile, is known for being rich in color but more of a darker hue, which some call blood red.
That material is “probably the oldest and most well-known … or was the most well-known,” Bradshaw said, noting there is virtually no production anymore; he sources South African rhodochrosite from old inventories.
In the United States, sources have been found in Montana and Colorado, the latter of which is known for the red material that comes from the Sweet Home Mine on Mount Bross.
Sweet Home started as a silver mine in the 1870s, at which time the rhodochrosite was just seen as waste rock, according to Steve Behling, the sales manager at Collector’s Edge Minerals.
The mine wasn’t very productive, failing to make a profit for the first few decades, according to the Gemmological Association of Great Britain, and also faced an onslaught of competition in the late 1800s as more and more mines opened.
Soon enough, though, those red crystals were recognized for their worth and started gaining value, becoming the mine’s sole focus.
Sweet Home produces some of the finest rhodochrosite in the world—vibrant, cherry red crystals—and helped it gain its status as the Colorado state mineral in 2002.
The mine has also been known to turn out some large pieces.
In 1992, it produced its largest yet, the Alma King—a rhodochrosite crystal measuring 14.25 centimeters on one side sitting on a quartz matrix more than 2 feet long, according to GIA’s Gems & Gemology.
The Alma King is currently in the collection of the Denver Museum of Natural History.
Modern production at the site has been handled by Bryan Lees and his two companies: Colorado Calumet Co. does the mining and Collector’s Edge Minerals markets and sells the mineral specimens. (The facetable rough is sent to Ohio-based Iteco Inc. for cutting.)
Active mining ceased at Sweet Home in 2004, but there’s been some activity nearby that should excite rhodochrosite lovers.
3. There’s new production at a storied source.
Lees initially leased the Sweet Home Mine but bought it outright in 1991. He operated the mine for more than a decade, pulling out collectable crystal specimens and facetable rough material.
In 2004, realizing they had reached the end of mining at that level of Mount Bross, Lees and his companies ceased operations at Sweet Home.
Between 1991-2004, Colorado Calumet/Collector’s Edge pulled out about $100 million dollars’ worth of mineral specimens in current dollar value, sales manager Behling said.
But Lees always wanted to go back, he added, knowing there were more red stones to be found in the mountain. So, he studied its geology and in 2016 received government approval to start mining again.
The new project is 200 feet above where they had been mining prior. Their first task was to drill and blast a 400-foot tunnel into the side of the mountain to get to the mineralized veins.
Sweet Home started as a silver mine in the 1870s, at which time the rhodochrosite was just seen as waste rock, according to Steve Behling, the sales manager at Collector’s Edge Minerals.
The mine wasn’t very productive, failing to make a profit for the first few decades, according to the Gemmological Association of Great Britain, and also faced an onslaught of competition in the late 1800s as more and more mines opened.
Soon enough, though, those red crystals were recognized for their worth and started gaining value, becoming the mine’s sole focus.
Sweet Home produces some of the finest rhodochrosite in the world—vibrant, cherry red crystals—and helped it gain its status as the Colorado state mineral in 2002.
The mine has also been known to turn out some large pieces.
In 1992, it produced its largest yet, the Alma King—a rhodochrosite crystal measuring 14.25 centimeters on one side sitting on a quartz matrix more than 2 feet long, according to GIA’s Gems & Gemology.
The Alma King is currently in the collection of the Denver Museum of Natural History.
Modern production at the site has been handled by Bryan Lees and his two companies: Colorado Calumet Co. does the mining and Collector’s Edge Minerals markets and sells the mineral specimens. (The facetable rough is sent to Ohio-based Iteco Inc. for cutting.)
Active mining ceased at Sweet Home in 2004, but there’s been some activity nearby that should excite rhodochrosite lovers.
3. There’s new production at a storied source.
Lees initially leased the Sweet Home Mine but bought it outright in 1991. He operated the mine for more than a decade, pulling out collectable crystal specimens and facetable rough material.
In 2004, realizing they had reached the end of mining at that level of Mount Bross, Lees and his companies ceased operations at Sweet Home.
Between 1991-2004, Colorado Calumet/Collector’s Edge pulled out about $100 million dollars’ worth of mineral specimens in current dollar value, sales manager Behling said.
But Lees always wanted to go back, he added, knowing there were more red stones to be found in the mountain. So, he studied its geology and in 2016 received government approval to start mining again.
The new project is 200 feet above where they had been mining prior. Their first task was to drill and blast a 400-foot tunnel into the side of the mountain to get to the mineralized veins.
This image shows where the new Detroit City Portal is compared with the original Sweet Home Mine site. (Photo courtesy of Collector’s Edge Minerals Inc.)
Mining activity at the Detroit City Portal (Photo courtesy of Collector’s Edge Minerals Inc.)
They started to find pockets in late 2018, Behling said, and mineral specimens started hitting the market that year.
Facetable rough took longer to find, and cut stones from the new project just started coming out last summer, Iteco’s Paul Cory confirmed.
The two working areas are not connected underground—just located on the same mining site—so they gave the new one a different name but retained Sweet Home for marketing reasons; it’s been dubbed the Detroit City Portal at the Sweet Home Mine.
So far, production hasn’t quite been at the level of Sweet Home, Behling said, but noted it can be scattershot anyway.
“I can tell you for a fact that even in the original mine, it sometimes would be six months to a year in between major pockets. You’d move a lot of rock and once in a while, nature would give you a gift where you had this beautiful pocket of crystals. It’s a very feast-or-famine kind of mining.”
When speaking to facetable material from Detroit City, Cory said Sweet Home produced more rough per season than the new working area.
Part of that does have to do with the mining company’s increased ability to get crystals out undamaged, meaning they will be kept as mineral specimens rather than being cut.
But he put it this way: “To give you a scale of the supply, probably all of [National Jeweler’s] readers could carry the entire gem rough supply in a single box from the vault to their car parked nearby.”
4. Rhodochrosite mineral specimens can go for much more than faceted material.
Mineral collectors love when the specimens feature a crystal in matrix, rather than isolated or broken fragments, Behling said.
These kinds of pieces are rare, and when they do find them, collectors gobble them up.
Some of the specimens from Sweet Home sold for $500 or $1,000 per piece, Behling said. But it’s also not unusual, he added, for Collector’s Edge to sell individual pieces for six figures.
“You may have a 3-inch-by-3-inch piece of matrix with several crystals on it, and it’ll be $100,000 or it’ll be $150,000.”
5. But faceted material is still highly coveted.
Sources also rarely turn out transparent material that can be faceted, and these pieces, too, are in high demand from buyers.
Gemstone cutter and wholesaler Bradshaw said when he recently held a virtual Tucson event, he sold out of several stones, and rhodochrosite was one of them.
Iteco’s Cory said, “The demand far exceeds the supply, and the market grows every year. The demand is worldwide, focused primarily on Japan, India, and the U.S. market. As more people become aware of the beauty of faceted rhodochrosite, the market becomes even larger.”
But rhodochrosite is not only low in supply; it also contains a few gemological characteristics that present a challenge for faceting.
First, it has perfect cleavage in three directions, so cutters must make sure they don’t put a large facet parallel to a cleavage plane, Cory said, which makes it more difficult to polish.
It also has a hardness of only 3.5-4 on the Mohs scale, so the stone is best set in earrings or necklaces, pieces that tends to take less abuse than rings or bracelets.
“You may have a 3-inch-by-3-inch piece of matrix with several crystals on it, and it’ll be $100,000 or it’ll be $150,000.”
5. But faceted material is still highly coveted.
Sources also rarely turn out transparent material that can be faceted, and these pieces, too, are in high demand from buyers.
Gemstone cutter and wholesaler Bradshaw said when he recently held a virtual Tucson event, he sold out of several stones, and rhodochrosite was one of them.
Iteco’s Cory said, “The demand far exceeds the supply, and the market grows every year. The demand is worldwide, focused primarily on Japan, India, and the U.S. market. As more people become aware of the beauty of faceted rhodochrosite, the market becomes even larger.”
But rhodochrosite is not only low in supply; it also contains a few gemological characteristics that present a challenge for faceting.
First, it has perfect cleavage in three directions, so cutters must make sure they don’t put a large facet parallel to a cleavage plane, Cory said, which makes it more difficult to polish.
It also has a hardness of only 3.5-4 on the Mohs scale, so the stone is best set in earrings or necklaces, pieces that tends to take less abuse than rings or bracelets.
Additionally, rhodochrosite is strongly doubly refractive—light enters it and splits into two—so cutters must orient the rough to avoid making a stone look “sleepy” if pavilion facets appear doubled, Cory said.
Even with this extra care required, cutters definitely will roll the dice on rhodochrosite when given the chance.
“In previous years, I would never consider cutting melee rhodochrosite, but I do now,” Bradshaw said. “Because it sells.”
Cory said stones bigger than 3 carats have about doubled in price over the last five years, while those weighing more than 10 carats have risen even more, perhaps triple from when the original Sweet Home Mine project closed in 2004.
Even with this extra care required, cutters definitely will roll the dice on rhodochrosite when given the chance.
“In previous years, I would never consider cutting melee rhodochrosite, but I do now,” Bradshaw said. “Because it sells.”
Cory said stones bigger than 3 carats have about doubled in price over the last five years, while those weighing more than 10 carats have risen even more, perhaps triple from when the original Sweet Home Mine project closed in 2004.
EditorsSep 15, 2020
5 Things to Know About … Red Beryl
EditorsMar 16, 2020
5 Things to Know About … ForditeMore on Editors
The Latest
AuctionsOct 27, 2025
Napoleon Left This Brooch Behind, And Now It’s Up For AuctionIt is part of Sotheby’s “Royal & Noble Jewels” sale along with an ornate hair ornament and an old mine-cut light pink diamond ring.
Events & AwardsOct 27, 2025
Hill Management Group Hired to Help Atlanta Jewelry ShowHill Management Group will oversee, market, and produce next year’s spring show.
CrimeOct 27, 2025
Arrests Made in Louvre Jewel Heist One of the individuals was apprehended at the airport as he was trying to flee the country.
Brought to you by
DESERT DIAMONDS: The Newest Trend in Natural Diamond JewelryFrom sunlit whites to smoky whiskeys, introduce your clients to extraordinary diamonds in colors as unique as their love.
MajorsOct 27, 2025
Target to Cut 1,800 Corporate JobsThe retailer, which has faced struggling sales in recent quarters, is looking to streamline its operations.
Weekly QuizOct 16, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
AuctionsOct 24, 2025
Bonhams Under New Ownership, Top Executives ReplacedLondon-based investment firm Pemberton Asset Management acquired the auction house for an undisclosed amount.
GradingOct 24, 2025
DMIA to Hold Diamond Testing Instrument DemoThe workshop will give attendees the chance to try out and ask questions about three different diamond verification instruments.
Brought to you by
Are Earrings an Overlooked Category? What Retailers Need to Know NowAs the holiday season quickly approaches, consider stocking one category that sometimes gets overlooked: earrings.
CrimeOct 24, 2025
Video Emerges of Louvre Jewelry Robbers Fleeing the Scene The footage shows two of the jewelry heist suspects descending from the second floor of the museum and then escaping via scooter.
CollectionsOct 24, 2025
Piece of the Week: Wyld Box Jewelry’s ‘Ray of Light’ EarringsFounder and designer Rosanna Fiedler looked to a vintage Cartier clutch when designing the sunlight-inspired drop earrings.
FinancialsOct 23, 2025
Jewelry Sales Resilient Despite Struggles at LVMH, KeringThe luxury conglomerates faced a challenging Q3 amid geopolitical and economic tensions.
SourcingOct 23, 2025
Petra Diamonds Turns to Shareholders to Raise Capital The struggling diamond mining company, which owns the historic Cullinan mine, has launched a rights issue to raise about $25 million.
WatchesOct 23, 2025
‘Million Dollar Hip Hop Watches’ Recounts Watch HistoryThe book details the journey of watches as symbols of hard-earned success in hip-hop for artists like 2Pac, Jay-Z, and more.
AuctionsOct 23, 2025
Freeman’s | Hindman Names New VP, Senior Specialist for Jewelry & WatchesAlexis Vourvoulis, who most recently worked at Tiffany & Co., brings more than two decades of jewelry experience to her new role.
TrendsOct 22, 2025
The Taylor Swift Effect: Antique Diamonds EditionThe superstar’s August engagement put the stamp of approval on an already hot engagement ring trend.
TrendsOct 22, 2025
Don’t Forget These Diamond Jewelry Trends When Stocking for the HolidaysRetailers should offer classic styles with a twist that are a perfect fit for layered looks, experts say.
AuctionsOct 22, 2025
Pink Diamond, Vanderbilt Jewels to Headline Phillips’ Geneva AuctionThe nearly 7-carat fancy vivid purplish pink diamond could sell for around $9 million.
SourcingOct 22, 2025
In ‘Storied Diamond,’ Jared Jewelers Is Emphasizing the Journey The retailer’s new collection of engagement rings and fashion jewelry is set with natural diamonds that are traceable via blockchain.
CollectionsOct 22, 2025
Tiffany & Co.’s ‘Bird on a Rock’ Finds New PerchChief Artistic Officer Nathalie Verdeille has reimagined the iconic design in both figurative and abstract creations.
Events & AwardsOct 22, 2025
JFC Kicks Off Halloween Costume ChallengeFive dollars buys one vote toward an industry professional you want to see dressed up as a hero, or a villain, this Halloween.
Events & AwardsOct 22, 2025
Hillsborough Antique Show Gets New OwnerRecently acquired by KIL Promotions, the November edition of the public show in San Mateo, California, will be held Nov. 7-9.
GradingOct 21, 2025
GIA Examines Rare Bicolor Pink DiamondThe stone’s two zones, one pink and one colorless, may have formed at two different times, the lab said.
MajorsOct 21, 2025
Pomellato Brings ‘Global Attitude’ to Rodeo Drive FlagshipHollywood glamour meets Milanese sophistication in the design of Pomellato’s new store in Beverly Hills, California.
Lab-GrownOct 21, 2025
Grown Brilliance Opens First FlagshipThe New York City store showcases a chandelier with 1,500 carats of lab-grown diamonds designed by an FIT student.
Events & AwardsOct 21, 2025
‘Douriean Fletcher: Jewelry of the Afrofuture’ Opens at MADThe Museum of Arts and Design's new exhibition features 75 pieces by the designer, best known for her work in the “Black Panther” films.
AuctionsOct 20, 2025
Sotheby's To Auction 10-Carat Vivid Pink DiamondMaking its auction debut, "The Glowing Rose" is expected to fetch $20 million at the November jewelry sale in Geneva.
SourcingOct 20, 2025
2 Mozambique Police Officers Killed at Gemfields’ Ruby MineThey were attacked on Oct. 15, as approximately 40 miners without licenses marched on the mine’s gate.
