Where is Petoskey Stone found?
Petoskey Stone (Hexagonaria percarinata)
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Open the appPetoskey Stone occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Petoskey Stone
Michigan, USA
Predominantly found along the shores of Lake Michigan and Lake Huron, particularly in the northern Lower Peninsula of Michigan, including Petoskey, Charlevoix, and other coastal areas. It is the state stone of Michigan.
Other Devonian outcrops
Similar fossilized rugose corals (Hexagonaria species) can be found in other Devonian-aged marine sedimentary rocks globally, but the specific Hexagonaria percarinata and its abundance leading to the 'Petoskey Stone' designation is unique to Michigan.
Collecting tips
- Search along shorelines. The best places to find Petoskey Stones are along the beaches of Lake Michigan and Lake Huron, especially after storms or during periods of low water levels, as wave action exposes and polishes them.
- Look for wet stones. The distinctive hexagonal pattern is much more visible when the stone is wet. Many collectors carry a small spray bottle of water to help identify them.
- Examine gravel pits and road cuts. Sometimes found in gravel pits or road cuts that expose Devonian-aged sedimentary layers in northern Michigan.
- Distinguish from other rocks. Be careful not to confuse them with other patterned rocks or chert. The hexagonal pattern is key.
Quick Check
- Color:
- Gray to tan/brown, often darker when wet.
- Luster:
- Dull to earthy (unpolished), vitreous to waxy (polished).
- Streak:
- White (due to calcite composition).
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