With winter ice off the Great Lakes, spring is one of the best times to get out along the shore and search for agates.
Known for their colors and patterns, collectors are often amazed at agates that turn up on Upper Peninsula lakeshores, with some known to be up to 20 pounds, according to the Michigan Department of Natural Resources.
Agates are a form of quartz and can be translucent — and in some cases completely transparent.
The stones — which can feature bands, circles, burst patterns and other designs — are a favorite of rockhounds. Rockhounding, or rock collecting, is a favorite pastime for visitors and residents who live in Michigan or simply visit its U.P. beaches.
Lake Superior beaches are among the best places to search out the stones, which can be hard to identify before being polished.
Here’s what to know about agates and where you can find them in Michigan:
Where can I find agates in Michigan? 10 Lake Superior spots to try
The stones can be found across multiple locations in Michigan’s Upper Peninsula, some of the best known spots along Lake Superior include:
How do I know my stone is an agate?
“Agates are sometimes hard to identify, even for the experts,” Mary Ann St. Antoine, a senior environmental quality analyst in the Marquette District Office of EGLE, said in a 2024 news release.
Antoine said for a dull waxy luster. Often, agates are red, orange or brown with a pock-marked surface.
Agates are translucent, which can hard to tell from the outside — hold them up to the light and see if they transmit a little light.
Michigan’s geology also includes a number of stones that people confuse for agates. Michigan Rockhounds said imposters include chert, banded flint, vesicular basalt, Mary Ellen jasper, fedspar with quartz and mica, and amygdaloidal rhyolite.
How are agates formed?
Agates are formed when gas bubbles in ancient lava leave a hole in the “vesicle” in the rock, according to the Michigan Department of Environment, Great Lakes, and Energy.
Silica (silicon dioxide) solutions flow through cracks into the holes in the host rock and fill them up over time, creating colorful variations.
Different chemicals in the solution cause the bands to be different colors.
When is the best time to look for an agate?
EGLE says the best time for Michiganders to look for agates is after a storm, when the waves have washed up new rocks along the coastline. Spring is a great time because winter ice pushes and rearranges sand and stones along the Great Lakes shorelines and turns up new specimens each year.
Techniques for identifying rocks
These identification techniques, according to the EGLE, can help rock hunters determine the type of rocks they have:
Appearance
Unique properties
Unique properties
Is there a limit on how many rocks a person can collect?
According to the EGLE, one person can not exceed 25 pounds total per year on state-owned and public trust lands.
Detroit Free Press contributed reporting.
This article originally appeared on Detroit Free Press: Searching for colorful Michigan agates? 10 spots to try this summer
Reporting by Jalen Williams, USA TODAY NETWORK / Detroit Free Press
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