Petoskey stones are easily the most known beach rocks of Michigan. These unique coral fossil stones are found by rockhounds throughout Michigan and are used to make beautiful jewelry, decor, and pieces of art. So, next time you're walking along the beach in Northern Michigan, look down and you may just find a Petoskey stone.
Here are some great tips to help you in your search for this lovely Michigan gem!
1. Know Your Petoskey Stones
Finding this fossil stone won’t happen just anywhere! Keep your eyes peeled for limestone rock strata – mixtures of limestone and shale. The stones are named for the area in which they are most often found. These stones are most prevalent in the Traverse Group in Michigan’s Lower Peninsula or “the LP”. They are easiest to find around Charlevoix or, you guessed it, Petoskey! The best place to begin your search is on a rocky lake beach wherever other lake rocks or coral abound.
2. Know When to Look
If you can tolerate the cold, right after the first thaw is the best time to go look. If you’d rather it be a bit warmer, any time in early spring will be best as the winter ice helps the lake waves bring new stones up from their deep sleep. If you wait until the lake warms a bit and snorkel out just a way beyond the shore, you may find some bigger stones that didn’t quite make it all the way to shore.
3. Know What to Look For
If you know that these beautiful stones exist, chances are you already know what they look like. If you’ve only ever seen them in gift shops, however, know that these are polished and finished stones. Petoskey stones in their natural state can be smooth but are more often bumpy and possibly, even probably scratched. Also, the deep black luster of the gift shop stones is brought out by polishing, too. These stones tend to be greyish in color and not shiny.
If you have never seen these stones before, know that they are both stones and fossils. They boast a beautiful six-sided floret pattern across the surface. They are fossilized rugose coral communities and you can almost see the life that these ancient beings used to have.
4. Have a Seat and Relax
If you take some time to gently move the visible stones to see below the top layer, you may be able to find a few stones that escaped others in years past. Many stones wash to shore from the bottom of the lake each year and not all of the Petoskey stones that wash ashore can be seen or are found their first season on land. So, take a seat in the sand, relax, and look for some of these hidden stones. Some of the best ones may yet be buried!
5. Be Mindful of Beaches and Property
There are places that prohibit the removal of Petoskey stones such as Sleeping Bear Dunes State Park. Michigan also has a restriction for picking up the stones that limit removal to 25 lbs. of stone per visit. If you find a stone that is larger than 25 lbs. Michigan reserves the right to confiscate it. The largest Petoskey stone on record is 8,000 lbs. and is displayed in the Besser Museum in Alpena.
If that’s a little too far for you, stop in at Detroit’s DNR Outdoor Adventure Center. They have one of the largest collections of found natural objects in the state and are permanently displaying the 93 lb. Petoskey stone found near Northport in 2015.
Where Else to Find Petoskey Stones
While these stones are named for their home in Michigan, it is not their sole place of residence. They can be found anywhere there are Devonian aged fossil beds exposed. The Ohio river valley has one of the deepest natural exposures and Petoskey stones have been found there as well as other states in the glacier’s path: Iowa, Indiana, and Illinois.
Places with other natural exposure or deep erosion such as New York, Canada, Germany, England, and Asia have also laid claims of ownership to Petoskey stones.
Polishing Your New Gems
Once you find your treasure, you’re going to want to bring out the best in it! This means a polishing process. You can find a local lapidary to do this for you or, if you’re more of a do-it-yourselfer, you can follow these simple steps:
- Use a stone file to get rid of the roughest bumps
- Now you will dampen your stone with a sponge or wet cloth and sand out the scratches. You don’t want anything with a grit too low as you could take off more than you mean to. These stones only rank at a 3 on the Mohs Scale of Hardness whereas a diamond – the hardest stone – is a 10. For this reason, you wouldn’t want to put them in a tumbler unless you are experienced with stones of different hardness. If you can see some scratches, you’ll want to use 220 grit sandpaper. Always sand in small, circular motions. Remember to rinse your stone or dunk it in clean water often as you sand. Once you feel confident most of your main scratches are out, you’ll move to a 400 and then 600 grit sandpaper. Take your time with the 600 grit as this will ensure you get the best finish with no scratches.
- If you have rubbing compound for your car, you can use this in the next step. There is also a compound specifically for stones if you’d rather use that. Lightly dampen a piece of corduroy or velvet and get about a quarter-sized amount of compound on your fabric. Use the same polishing method as you used before; small circular motions from top to bottom.
- If you see any scratches after this, you will return to your 400 and then 600 grit sandpapers and repeat the process.
- Once you are satisfied that you have no scratches, wipe your stone off with a damp cloth and reveal that beautiful shine!