fossil
Petoskey Stone
Hexagonaria percarinata
Hardness: 3-3.5 on Mohs scale; Color: Gray and white with distinctive hexagonal coral patterns; Luster: Dull to pearly when raw, glossy when polished; Structure: Calcite coral colony
- Hardness
- 3-3
- Color
- Gray and white with distinctive hexagonal coral patterns
- Luster
- Dull to pearly when raw, glossy when polished
Identified More fossil →
Explore Petoskey Stone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3-3.5 on Mohs scale; Color: Gray and white with distinctive hexagonal coral patterns; Luster: Dull to pearly when raw, glossy when polished; Structure: Calcite coral colony
Formation & geological history
Formed by the fossilization of colonial rugose coral during the Devonian period, approximately 350-400 million years ago, in marine environments.
Uses & applications
Primarily used for lapidary work, jewelry, stone carving, and as a popular collector's item and Michigan's state stone.
Geological facts
The name comes from Chief Pet-O-Sega of the Ottawa tribe. The distinctive pattern is the fossilized skeletons of individual coral polyps.
Field identification & locations
Identified by the unique six-sided 'honeycomb' or sunburst pattern visible when wet. Commonly found along the shores of Lake Michigan and Lake Huron.
More like this
Other fossil specimens
Crinoid Stem Fossil in Matrix
Phylum Echinodermata, Class Crinoidea
fossil
Sedimentary Outcrop (Sandstone/Shale)
Sedimentary bedrock formation (variable composition)
sedimentary
Fossiliferous Limestone
Fossiliferous Calcilutite / Biomicrite
sedimentary
Fossiliferous Limestone
Biogenic Limestone with Brachiopod/Crinoid fragments
sedimentary
Fossilized Crinoid Stem in Limestone
Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix
fossil
Fossiliferous Limestone
Limestone with embedded fossil cross-section
sedimentary