Crosby’s mine pits were once the only place to find unique gemstones

Rockhounds hope Minnesota laws will some day allow collection

By Travis Grimler

Ask rockhounds what they know about Minnesota and they will more than likely mention Lake Superior agate.

A few who are familiar with the rarer finds along the shore of Lake Superior in Duluth might talk about Thomsonite and Petoskey stones, Yooperlites or some of the other rarer types. But most will come back to Lake Superior agate, the state stone.

There is, however, a stone far rarer and found only in one place — the Cuyuna Iron Range.

From 1911 until 1984, the Cuyuna Iron Range was a massive iron mining operation, famous across the nation.

As with other mining operations, the job was made possible by digging through layer after layer of soil and stone to reach the many hundreds of years of material deposited and eventually developed by pressure, chemical processes and age into different layers.

Miners were obviously after iron ore, but to get it, they had to remove mountainous piles of unwanted material called tailings. And this is how a mineral unique to the Cuyuna Iron Range came to the light of day.

Miners often come across other materials during their work. Some might find materials as valuable, or more than what they are mining. Some find fossils, like in the Mesabi Iron Range.

In Cuyuna, it was a special combination of layered stone: quartz, siderite, iron, manganese, epidote and sometimes asbestos combining in thin, layered patterns to create a stone that caught the eyes of miners and those who simply liked picking through the tailings piles.

One such person was Bill Bingham, co-founder and first president of the Minnesota Mineral Club. While it is possible that many had already collected similar samples, Bingham was the first to publish an official description of the material in 1936.

For that, he earned the honor of lending the mineral its name — Binghamite.

“Mr. Bingham was the owner of one of the mines,” said Edward Opatz, president of the Cuyuna Rock, Gem and Mineral Society.

“He was a geologist, then he got into finding this stuff. He knew it wasn’t iron ore, but it was something that really caught his attention, and he had his own really big personal collection.”

The way the different minerals in binghamite lined up made it desirable to collectors even while the tailings were still piling up. Instead of quarter-inch thick layers like the banded iron, it formed almost fibrous crystal layers that reflect the sun in a way that isn’t common to many minerals.

This quality, called “chatoyancy” after the French phrase for “cat eye like,” is what makes tiger’s eye pretty. Found alongside Binghamite and possibly over lapping with categorization are two other stones, Minnesota tiger’s-eye and silkstone.

“It’s kind of like opal, where you look at it in different light and it shows you different colors and different variations,” Opatz said.

This large piece of Binghamite from Bill Trombley’s collection shows the variability of Binghamite in its fibrous crystal layers. Contributed / Bill Trombley

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“It’s unique just because of the heat and pressure when it was being made.”

After Bingham described the stone, it became collectible like Lake Superior agates. Rockhounds could be found picking through the piles of stone throughout the iron range looking for bucketloads of the material.

“Most of (Bingham’s collection) came off the tailings piles,” Opatz said. “They rejected those stones because there was no iron ore value to it. Most of the piles out in the state park had Binghamite in them. There’s probably some still down on the bottom of the lakes, but you’re not going to find them that easy.”

When the mining operations closed in 1984, Binghamite went from not only a collectible, but a stone with limited quantities.

“It was hard to come up with good quality Binghamite, because there wasn’t any more earth being moved,” said Bill Trombley, a rockhound. “The mines are all lakes, so you’re stuck with all the tailing piles.”

Without materials being removed and crushed for mining, the only stones that would be available were the ones already stacked in the Cuyuna area, and that attracted rockhounds from all over the state

“I belong to two different clubs in the area and I first started to learn about Binghamite and develop an interest in it,” Trombley said. “It was when we could do field trips there in Crosby back in the early ‘90s. When I got into it (the city) owned the Yawkey Mine just north of Crosby and you could pay a camping fee and we would take our kids up there and back to the old dump piles.”

Collection continued for nine years before a major change put an end to most recreational gathering of Binghamite. In 1993, the Cuyuna Country State Recreation Area was adopted into Minnesota Department of Natural Resources management, becoming a state park.

“The state park is off limits to collecting, because it’s a state park,” Opatz said.

With the designation came the rules that cover all state parks. Mushroom and berry collection is allowable, but no flowers, living plant material, artifacts or — most relevant, rocks — could be removed.

Binghamite hunting was outlawed throughout most of the traditional rockhounding locations.

“I ran into a DNR guy in Ironton right after they had purchased the Yawkey Mine from the city of Crosby,” Trombley said. “He told me he’d have me arrested if I ever picked up a rock there.”

There may be some exceptions for private land; however, there is little land that would be suitable for Binghamite collection, even if landowners are willing to offer permission.

“There are supposed to be some on private property,” Opatz said. “There are some on private property with tailings piles, but most of them are not really interested in letting people come on their property. Hopefully that will change someday.”

Still, the stones in old collections have become almost heirloom-like. Trombley once had an enormous collection, but it dwindled over time.

“I sold my smaller stuff and got rid of a lot of other stuff,” Trombley said. “Especially when I moved into a two-bedroom, twobath apartment. I found out I couldn’t keep 2,000 pounds of rocks over here so it’s been reduced.”

There was once an abundance of collectors who had likely accumulated large quantities of the materials. Many of those stones have since changed hands, even to the point that a great many polished Binghamite stones and mounted jewelry pieces can be found at RW Jewelers & Boutique in Nisswa.

Still, there is some hope that there eventually could be a way to open up Binghamite hunts in the recreation area with state permission.

“We’ve been talking to the state trying to get it available as a recreational hobby,” Opatz said. “That way they would let us have one little space where people could look for rocks and keep some of them.”

Some compare the compromise to fossil collecting on the Mesabi Range. The Hill Annex Mine on the Mesabi Range dug through a cretaceous rock layer and uncovered fossils from ocean creatures from when Minnesota was underwater.

Until recently, the park allowed those participating in park tours to not only see the tailings pile full of fossils, but to pick and keep them.

Hill Annex was different, however, as the

A pendant displaying the variation of Binghamite colors, including red, gray and white, can be found at RW Jewelers & Boutique in Nisswa.

Travis

Grimler / Echo Journal tailings pile for the fossil hunt was located on county property abutting the park.

Though it is not in the cards now, the rare Binghamite stones in Cuyuna could pose yet another draw to the retired mining area. Those who don’t want to visit for the miles and miles of intricate bike trails might instead want to hike the hills looking for rare stones, bringing even more tourists into the area.

Other states have developed successful programs that attract visitors for a chance to sift through dirt for rare stones. Crater of Diamonds State Park in Arkansas, for example, attracts over 100,000 paid visitors every year.

There is demand for the same type of attraction in the Cuyuna Range.

“Every year I get six to 10 people from out of state asking where they can collect Binghamite,” Opatz said. “I tell them sorry, because you can’t collect it because it’s in the state park.”

While there is no indication that any change is forthcoming, rockhounds can still hold out hope that someday they can find their own prized Binghamite.

TRAVIS GRIMLER is a staff writer for the Pineandlakes Echo Journal weekly newspaper in Pequot Lakes/Pine River. He may be reached at 218-855-5853 or travis. grimler@pineandlakes.com.