If you're in Michigan, or if you're travelling to Michigan, you've likely heard the buzz about some pretty awesome-looking stones. Michigan is home to a unique type of fossil known as a Petoskey stone. These stones have a beautiful honeycomb-shaped pattern across their surface that can be enhanced by polishing the stones.
What Are Petoskey Stones?
Petoskey stones are the fossilized remains of a few species of colonial, or group-living, corals. Though you might find it hard to picture now, about 350 or 400 million years ago Michigan was located in tropical regions near the equator. At that time, land which is now found quite a ways north was covered by shallow seas filled with oceanic life and coral reefs.
Over the course of those hundreds of millions of years, the tectonic plates shifted and moved Michigan to its current location. However, the fossilized remains of those ancient tropical corals – a few species in the taxonomic genus Hexagonaria – still pop up relatively frequently across the state.
Where Can You Find Petoskey Stones?
You can find Petoskey stones at a number of different beaches and state parks throughout Michigan. The following locations will provide the best opportunities for finding Petoskey stones:
- Beaver Island
- Fisherman’s Island State Park
- Lake Michigan Beach
- Mt. McSauba Beach
- North Point Nature Preserve
- Pt. Bestie Lighthouse
- Empire Beach
- Leelanau State Park
- Orchard Beach State Park
- Bayfront Park West
- Bayshore West Park
- Magnus City Park Beach
- Petoskey State Park and Campground
- Sunset Park
- Elk Lake
- Peterson Park
- Point Betsie Lighthouse
How to Find Petoskey Stones
Sandy beaches might work well for sunbathers, but rocky beaches are best if you're hunting for Petoskey stones! It's easier to spot the honeycomb pattern on these stones if the rock has been submerged in water or otherwise moistened by the waves or tide, so you're more likely to have success searching near the waterline.
Another way to increase your chances of finding Petoskey stones is to search after a storm, as the activity is likely to move or dislodge stones that might have previously been deeper in the water or buried beneath other rocks. You're also more likely to find these stones if you search areas less trafficked by other beachgoers, such as regions farther from parking lots.
Is It Legal to Collect Petoskey Stones?
Before picking up the rare stone you just spotted, double-check to ensure that you're legally allowed to bring it home with you! Regardless of location, you're only allowed to collect a maximum of 25 pounds of stones per year in Michigan. Additionally, you cannot collect these stones from any federal land, such as national parks. You are welcome to observe the stones on national park land, but you cannot take them home with you.
Stick to public parks and state parks for collecting these stones.
Polishing Petoskey Stones
The best way to bring out the natural beauty of these stones is to polish them. However, you don't want to use a rock tumbler to polish Petoskey stones as it will damage them. Instead, you'll need to polish them by hand, always making sure to use appropriate safety gear.
You can carefully use a file to shape the stone into a smooth surface. After doing so, use rough grain sandpaper to continue smoothing the surface. Using finer and finer grain sandpaper, continue to sand down the surface, rinsing and drying the stone between to check for rough spots. Once smooth, use a cloth and polishing powder to polish the surface.
- Finding Petoskey stones is like finding a small piece of Michigan's history. Kids and adults alike will enjoy exploring all the many different places Petoskey stones are likely to turn up. Take a bucket along with you to gather any specimens you might find.
About the Author
Marina Somma is a freelance writer and animal trainer. She holds a B.A. in Psychology and a B.S. in Marine and Environmental Biology & Policy from Monmouth University. Marina has worked with a number of publications involving animal science, behavior and training, including animals.net, SmallDogsAcademy and more.