Michigan’s shoreline is an amazing place for rock hunting because there are a wealth of beautiful stones and plenty of parks and beaches from which to access Lake Michigan.
Collecting stones and fossils — also called rockhounding — is a very personal experience as it differs what people find appealing to collect. I am personally a big fan of stones with holes, patterns and concretions. Listed below are a few of my favorites to look for when walking along the beach.
Crinoids — These fossils were part of the stems section of an animal that is a distant relative of the starfish. They look like small disks, and often have a hole through them. Crinoids are quite abundant in the area and are a popular item for handmade jewelry.
Favosites aka “Honeycomb Corals” — These fossils consist of closely grouped calcitic tubes that resemble honeycomb. The pattern is much smaller than that of a Petosky Stone and looks more like a lace pattern.
Fossiliferous Limestone — These stones contain an abundance of fossils such as the shells of mollusks, crinoids, and other organisms. Though these stones are not necessarily pretty when you find them, they can be quite stunning when cut and polished.
Geodes — These rounded rock structures have a sparkling internal cavity lined with crystals. A rare and exciting find, they are formed when minerals crystalize inside of hollow cavities in stone. Geodes can be found in a variety of colors and mineral compositions.
Halysites — These fossilized corals look like interlocking strings of tiny chains.
Petoskey Stones — Yes, you can find Petoskey Stones in Southwest Michigan if you’re lucky. The official state stone of Michigan is easy to identify, especially when wet. These fossils consist of tightly-packed, six-sided corallites and have thin lines radiating out from a darker center.
Rugosa aka “Horn Corals” — These pieces of fossilized coral are easy to identify because of their unique horn like shape.
Sandstone — These common sedimentary stones come in a variety of colors. What I look for in sandstones are layering in different colors or patterns of color.
Septarian Nodules aka “lightning stones'' or “turtle stones” — These unique stones are found at a variety of beaches in Southwest Michigan. They were formed from iron rich mud/clay that cracked. Those cracks filled with calcite. The result is a fascinating looking stone that has a craquelure or lightning-like pattern of lighter color lines on a darker background.
I also enjoy finding stones that resemble something else. If you use your imagination, the beach is full of interesting potential. I have found stones that look like states, letters, fruits, hearts and more.
Tips for rock hunting:
- Looking for locations that are less popular so that there is less competition.
- Avoid maintained beaches because stones may be removed as part of cleaning.
- Be prepared to walk. Southwest Michigan has a sporadically-rocky shoreline, and you may have to walk some distance between rocky sections.
- Look close. There are many beautiful, but tiny, stones and fossils.
- Go out after wind storms. Waves on the lake move a lot of stone and push it up onto the shoreline. Wind storms can drastically change the shoreline, removing sections of stone and creating new ones in other areas. This is why spring and late fall are two of the best times to rockhound.
- Hunt after rain. It is a lot easier to identify stones when they are wet.
- Bring a bucket or bag to collect your finds.
While hunting for stones, be on the lookout for beach glass, smoothed bits of ceramic and slag. Although these are man-made garbage, over time the lake will smooth and beautify them, making them collectibles. While you are out rockhounding, I recommend carrying a garbage bag in order to dispose of garbage you find along the shore. Always strive to make the shoreline even prettier than you found it
Important note: While out rock hunting please keep in mind that it is illegal to remove stones from a National Shoreline, and that there are limits to the amount you can collect from State Parks (DNR rules).