sedimentary

Fossilized Coral (Petoskey-like or Favosites)

Anthozoa (Fossilized Coral)

AI-generated identification · may be incorrect

Hardness: 3-4 (Calcite-based) to 6.5-7 (if Silicified); Color: Tan, beige, or white; Luster: Dull to waxy; Structure: Visible honeycomb or polyp patterns (corallites); Specific Gravity: 2.6-2.7.

Hardness: 3-4 (Calcite-based) to 6
Color: Tan, beige, or white
Luster: Dull to waxy

Identified May 9, 2026More sedimentary →

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Physical properties

Hardness: 3-4 (Calcite-based) to 6.5-7 (if Silicified); Color: Tan, beige, or white; Luster: Dull to waxy; Structure: Visible honeycomb or polyp patterns (corallites); Specific Gravity: 2.6-2.7.

Formation & geological history

Formed during the Devonian or Silurian periods (350-450 million years ago) when warm, shallow seas covered much of the interior of North America. These are the mineralized remains of ancient marine coral colonies.

Uses & applications

Commonly used in jewelry (pendants and beads), lapidary art, paperweights, and as educational geological specimens for collectors.

Geological facts

These fossils represent organisms that lived millions of years before dinosaurs. While Michigan is famous for Petoskey stones (Hexagonaria), similar Favosites fossils (honeycomb corals) are found globally in Paleozoic rock layers.

Field identification & locations

Identified by the distinct geometric pattern of pores or 'cells' on the surface of the stone. Often found on beaches of the Great Lakes or in limestone quarries and road cuts. Polishing often reveals more intricate details.