fossil

Honeycomb Coral Fossil

Favosites (extinct genus of tabulate coral)

AI-generated identification · may be incorrect

Hardness: 3-4 (calcite) or up to 7 (if silicified). Color: Grey, tan, or white. Luster: Dull to vitreous. Structure: Characterized by closely packed polygonal (hexagonal) tubes called corallites, resembling a honeycomb.

Hardness: 3-4 (calcite) or up to 7 (if silicified)
Color: Grey, tan, or white
Luster: Dull to vitreous

Identified July 8, 2026More fossil →

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Physical properties

Formation & geological history

Formed in warm, shallow marine environments during the Ordovician to Devonian periods (approx. 488 to 358 million years ago). They were reef-building organisms that became fossilized as the organic matter was replaced by calcium carbonate or silica.

Uses & applications

Used primarily for educational purposes, geological study, and as decorative collector specimens. Polished pieces are sometimes used in lapidary art.

Geological facts

The walls between the individual corallites are pierced by small pores known as mural pores, which allowed nutrients to be shared between the coral polyps. Large colonies could grow to several meters in size.

Field identification & locations

Identify in the field by the distinct 'honeycomb' pattern of small holes or hexagonal cells on the surface of limestone or loose river rocks. Commonly found in the Great Lakes region (USA/Canada), particularly on beaches.