Why are Petoskey Stones only Found in Michigan?

Did you ever wonder why Petoskey stones are only found in Michigan? Yeah, they’re named after a Michigan city, but so what? Does that mean they are only found in Petoskey?

Well, yeah.

Petoskey stones are fossilized coral and yes – found mostly in the area of Petoskey. But there are other coral fossils discovered in many other places around the world, so what’s the big deal? Why are Petoskey stones so special?

Get our free mobile app

They are special due to a few different reasons.

The coral species in particular is Hexagonaria. These coral thrived in a now-non-existent sea that covered parts of Michigan and most of North America approximately 350 million years ago. During the final Ice Age, glaciers moved and shifted across the Great Lakes , grinding down limestone that contained the coral fossils. As the glaciers moved and melted, these fossilized corals were left behind in various locations. According to Quora, “The specific conditions in Michigan allowed for the preservation and exposure of these stones.”

Northern Michigan’s geological makeup contains vast – almost infinite – amounts of limestone (and dolostone) which is a major factor in coral stone formation. The conditions surrounding Petoskey are especially unique. Geological conditions in other parts of Michigan don’t produce the same unique appearance of Petoskey stones, and Charlevoix stones are a good example of the difference.

All around the Michigan Great Lakes shores, people are finding fossilized coral, but for the real thing – Petoskey Stones – you need to look no further than Petoskey itself.

Take a look at a few Petoskey stones by scrolling down...