Timing can be everything when it comes to finding Lake Superior agates.
“It’s like treasure hunting,” says Butch Goldenstein of St. Cloud, an agate enthusiast who manned a table at the annual Agate Days celebration in Moose Lake earlier this summer. “There’s a thrill in finding them. And there’s nothing like walking in somebody’s footsteps and saying, ‘Oh, you missed this one.’ ”
Agate pickers live for those moments when they find these beautiful banded rocks, allowing them to connect with the region’s geology.
What makes Lake Superior agates so special? Formed in and around the lake during volcanic eruptions about a billion years ago, these gemstones were distributed across the landscapes of northeast Minnesota and northwest Wisconsin during a later bout of glacial activity, roughly 10,000 to 15,000 years ago. They come in a variety of shapes, sizes and colors, often with beautiful banding, luminescence and other features. Simply put, agates stand out from the plainer rocks that often hide them.
So they are treasured. Agates have been Minnesota’s official state gemstone since 1969.
While they can be purchased at rock and gem shops throughout the Upper Midwest, it’s so much more fun and rewarding to find them on your own. As an added bonus, agate-hunting makes for a great family activity.
Here are some tips on making your next excursion a success, whether it’s your first or your 50th time looking for agates:
KNOW THE LOOK
Understand that there is broad variety in agates, so it’s helpful to know the range of characteristics.
“I think you develop an eye for agates,” says Goldenstein, who has picked agates for more than 60 years. “That comes from picking up thousands of stones. Some are and some aren’t.”
One of the best clues is a waxy, almost glossy surface. Many agates are translucent, but some are more opaque.
Agates come in a range of colors, and iron oxide staining is found on most agates, with the most common shades being rust-red and yellow.
The agate’s famous bands aren’t always visible. Sometimes the bands face down in the dirt. Sometimes the rocks bear less orthodox patterns, without the classic cross sections. Other times the bands have broken away, leaving them partly peeled off, almost like banana skin.
Agates are generally round, since they were formed in bubble holes in lava. Look for pitting or dimples on the outer surface.
KNOW WHERE TO LOOK
The most obvious place to find agates — Lake Superior — is actually the least favorite of most expert rockhounds.