Introducing: Yooperlite

yooperlite hunting

In his job as a casino pit boss, Erik Rintamaki has watched hundreds of people hit a jackpot in the casino. 

But he never expected he’d strike gold on the beaches of Lake Superior.

Erik is a proud “Yooper,” living on the rugged shores of Lake Superior in Michigan’s Upper Peninsula. He grew up on the lake, collecting agates, rocks, and jars full of sea glass from the time he was a kid.

He’s an avid agate picker, beachcombing year round, even when the temperatures drop below zero. Agates are getting harder and harder to find in Michigan on Lake Superior, so he wanted to see if he could find a better way to spot them. An ad on eBay for an ultraviolet (UV) light showed glowing agates, so he decided to try looking for agates with a UV flashlight at night.

yooperlite glowing on the beach

“The first three times I went out, I found nothing,” he says. “On the fourth time, I was on my hands and knees at 4 am and I found a rock glowing bright fluorescent orange. I screamed with joy!”

The next day he tried to ID the rock, but had no luck with his searches for “fluorescent minerals in Michigan” or “orange glowing minerals.” Queries to other rockhounds, online groups, and websites also turned up nothing. There are other glowing stones on Lake Superior beaches, such as Petoskey stones, sandstone, and even limestone. But, nothing that glowed like what he had found.

yooperlite sphere

He started to suspect that what he had found was indeed something that hadn’t yet been identified. He brought samples to mineral experts Shawn Carlson and Ray Laughlin, who ran tests at Michigan Technological University and came back with the conclusion that it was indeed a new mineral. It’s technically “syenite class containing fluorescent sodalite” but Erik wanted something easier to pronounce. He coined the name “Yooperlite” while walking on the beach with his brother-in-law: “Yooper” for where they’re found and “lite” for the fluorescent sodalite that causes the glow.

hunting for yooperlites

When Erik’s discovery was announced in May 2018, things really got rocking and rolling. Erik began taking fellow rockhounds to the beach to show them how to find Yooperlites. One video that he posted of a local group finding Yooperlites went viral—with almost 200,000 views—and people all over the world started contacting Erik, wanting to learn about the rocks.

A Florida woman saw the video, called Erik on the phone, then packed up her camper and told her husband they were leaving in two hours.

“They drove two days straight through to Michigan,” he says. “They did the beach tour the first night, booked another the second night, and have already booked for next year.”

Erik now leads nighttime picking tours for those who want to experience the thrill of finding these glowing rocks. Groups meet up on the beach about an hour before dark, he gives each member a powerful UV flashlight, he marks the beach with glow sticks so no one gets lost, and Erik teaches each person individually how to find Yooperlites. He has had spouses show up all grumpy about tagging along on a nighttime beach hunt, and leave saying it was the best thing they’ve ever done.

“These stones are magical,” he says. “Until you experience the magic of hunting for and finding a piece of Yooperlite, you can’t understand.”

yooperlite glowing rock

Most of the tour members hold onto a few of their favorite rocks to bring home, and Erik buys the rest so he can share them through his appearances at rock and gem shows and on his website. He has created beautiful glowing Yooperlite sphere paperweights, carved slabs of Yooperlite into the shape of the Upper Peninsula, and he auctions the raw stones on eBay.

Erik makes sure that when his groups are picking up Yooperlites, they’re also picking up any trash they find. Lots of plastics glow under black light so it makes them easy to spot. As part of his “Clean the Beach” initiative, he asks each participant to bring back at least one piece of trash.

So what’s next? Erik’s already got a full-time job, but his Yooperlite tour business is taking off. Gem shows that he used to attend now call him to be a featured speaker. His son and a friend now help him with the tour business. He’s trademarked the Yooperlite name, and you can find T-shirts, hats, UV flashlights, and other Yooperlite gear on his website. News outlets from Forbes to CBS News to German television are captivated by his story, which is spreading like wildfire.

And these pieces of Yooperlite, which have been lying on the beaches of Lake Superior, hidden in plain sight, are now bringing magic to beachcombers around the world.

Visit to see more photos and videos, sign up for his email list to find out about 2019 tours, and check out to learn about minerals that might be glowing on your beach. All photos © Erik Rintamaki.

Learn more about beach rocks:

beach rocks agates rockhounds
Learn more about beach rocks including agates, Cape May diamonds, Yooperlites, fulgurite, puddingstone, and more. Articles ›

This article appeared in the Glassing Magazine November/December 2018 issue.


It would seem that Erik didn’t look very hard to find an identity for this mineral it is found all around the world.

Redhawk October 21, 2022

Found 5 pound Yooperlite

What is considered a large ether light? I found one that is exactly 5 pounds with brilliant color June 08, 2022

Bucket lister for me! Hopefully coming in 2020, or 21. I can’t wait!

Gina September 10, 2019

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