fossil

Fossil Coral (Favosites)

Favosites sp. (Extinct Tabulate Coral)

Hardness: 3-4 (calcite based); Color: Light gray to tan; Luster: Dull to earthy; Structure: Honeycomb-like pores (corallites) with internal horizontal dividers (tabulae); Cleavage: Rhombohedral at microscopic levels.

Hardness: 3-4 (calcite based)
Color: Light gray to tan
Luster: Dull to earthy

Identified July 19, 2026More fossil →

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Physical properties

Formation & geological history

Formed through the permineralization of ancient coral colonies, primarily during the Silurian to Devonian periods (approx. 430-360 million years ago) in warm, shallow marine environments.

Uses & applications

Used primarily as decorative stones, educational specimens for paleontology, and occasionally in lapidary work for jewelry cabochons.

Geological facts

Commonly known as 'honeycomb coral' due to the distinctive shape of the skeleton. They were colonial animals that lived in the oceans long before the first dinosaurs appeared.

Field identification & locations

Look for the distinct geometric honeycomb pattern on the surface of gray shoreline pebbles. They are commonly found in the Great Lakes region of North America, particularly on the shores of Lake Michigan and Lake Huron.

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