Immerse yourself into the Charlevoix rock hound culture by finding some Petoskey stones. Petoskey stones are actually fossilized coral from over 350 million years ago during the Devonian period when Michigan was covered by warm seawater. Over time the continents shifted from then, Michigan being near the equator to where Michigan now lies in the middle of the freshwater Great Lakes. When you find a Petoskey stone you hold in your hand a fossil of colonial coral which predates humans by about 300 million years.
The Charlevoix area beaches are touted as one of the best places to look for them, though they are found across the entire top third of the lower peninsula in gravel pits and road beds. Look for Petoskey stones at Fisherman's Island State Park, Michigan Beach, McSauba Recreation Area/North Point Nature Preserve.
Choosing a time to go is important because the stones shift with the weather and waves. On windy wavy days, the stones may all wash out into the lake or may wash into the shore and litter the beach. Where there are numerous rocks you can usually find Petoskeys. They are easiest to find when wet so the hexagonal pattern is visible. Don't discount going out in your raincoat when it's possible to find their yards away from the water. Remember, each person is limited to a 5-gallon bucket of Petoskey stones to take with you.
Part of the fun is hunting for your own Petoskey Stones, but they are generally for sale at many gift shops in the Charlevoix, Petoskey, and Traverse City areas