03/13/2026
There’s something special about seeing the hidden beauty inside a stone. ✨
This is a before and after of a Petoskey stone I worked on recently. The first photo shows how it looked when I found it—weathered, chalky, and hiding its story beneath the surface. After grinding and polishing, the famous honeycomb pattern appeared, revealing the fossilized coral that makes Petoskey stones so unique.
Petoskey stones are actually fossils of an ancient coral called Hexagonaria percarinata, which lived in warm shallow seas about 350 million years ago during the Devonian period. Long before the Great Lakes existed, this area was covered by tropical ocean!
During the Ice Age, glaciers scraped these fossils from bedrock and scattered them across what is now Lake Michigan. Wave action slowly tumbles and smooths the stones along the shoreline, which is why Michigan beaches are one of the few places in the world you can find them.
What makes polishing them so satisfying is the process:
• First the rough outer surface is ground away to expose the coral structure
• Then the stone is taken through several finer grits of sanding
• Finally it is polished to bring out the intricate hexagonal pattern that looks almost like a natural mosaic
When dry, many Petoskey stones look plain and gray—but once polished (or even just wet), the fossil pattern comes alive.
Every one is completely unique, and it always feels like uncovering a tiny piece of Michigan’s ancient ocean history. 🌊🪨
