fossil

Fossilized honeycomb coral

Fossil coral, commonly Favosites or related tabulate coral

AI-generated identification · may be incorrect

A brown-gray, silicified or calcified colonial coral with polygonal to rounded corallite cavities and glossy wet luster. Original calcite aragonite skeleton may be replaced by silica; hardness is typically 3–7 depending on preservation, with no consistent cleavage.

Identified September 15, 2026More fossil →

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Physical properties

Formation & geological history

Formed when colonial marine coral skeletons accumulated in Paleozoic shallow seas, commonly Ordovician–Permian, then were buried and mineralized during diagenesis. The honeycomb-like pits are individual corallite chambers.

Uses & applications

Primarily a collectible and educational fossil; polished fossil coral is also used decoratively and occasionally in jewelry. It has little construction value as an individual specimen.

Geological facts

The cavities are biological structures, not gas bubbles or drill holes. Tabulate corals were reef-building animals and are important indicators of ancient warm, shallow marine environments.

Field identification & locations

Identify it by repeated corallite tubes or pits, fossil texture, and irregular colony growth; acid may weakly fizz if calcitic, while silica-replaced material does not. Common sources include Indonesia, Morocco, the Great Lakes region, and Australia.