fossil

Fossil coral (likely tabulate or colonial coral)

Fossilized colonial coral; exact genus indeterminate from the photograph

AI-generated identification · may be incorrect

Small rounded specimen with tightly packed polygonal corallite cups and dark mineral-filled cavities in a pale gray-brown matrix. Original aragonite/calcite skeleton is replaced or infilled by silica or calcite; hardness commonly 3–7 depending on preservation, with dull to slightly waxy luster.

Identified August 16, 2026More fossil →

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Physical properties

Formation & geological history

A colonial marine coral lived in a shallow Paleozoic–Mesozoic reef environment; after burial, its skeleton mineralized during diagenesis. The precise geological age cannot be determined visually.

Uses & applications

Primarily a geological specimen, teaching aid, or collectible; polished fossil coral is also used decoratively and occasionally in jewelry.

Geological facts

The repeated cup-like structures are individual corallites, showing that this was a colony rather than a single organism. Dark centers may represent sediment or secondary mineral infill.

Field identification & locations

Identify by the regular, repeated corallite pattern; coral fossils differ from vesicular volcanic rocks by having organized cellular geometry. Common in limestone deposits worldwide, including North America, Europe, Australia, and Asia.