fossil

Fossil coral pebble

Likely fossilized colonial coral, commonly Favosites or a related tabulate coral

AI-generated identification · may be incorrect

Honey-brown, polished/worn surface with a distinctive honeycomb pattern of polygonal corallite cells; mostly calcite, Mohs hardness 3, vitreous to dull luster, granular crystalline structure, and no obvious cleavage.

Identified August 23, 2026More fossil →

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Physical properties

Formation & geological history

A Devonian–Silurian marine coral colony was buried and mineralized, commonly by calcite, then eroded into a rounded pebble; exact age and species require locality and microscopy.

Uses & applications

Used as a decorative or educational fossil specimen and occasionally in cabochons or jewelry; not generally used industrially.

Geological facts

The repeated small chambers are individual coral corallites, not vesicles or ordinary rock pores. Similar fossil coral is famously collected in the Great Lakes region and other ancient shallow-marine limestone deposits.

Field identification & locations

Identify it by the regular honeycomb cells, unlike random cavities in volcanic rock; a vinegar or dilute acid test may fizz because of calcite, but can damage the specimen. Common sources include Michigan, Ohio, Indiana, Australia, and parts of Europe.