sedimentary
Fossilized Favosites (Honeycomb Coral)
Favosites (Genus), Phylum Cnidaria, Class Anthozoa
Hardness: 3-4 (calcite) or up to 7 (if silicified/replaced by quartz). Color: Typically tan, gray, or white. Luster: Dull to earthy. Structure: Characterized by small, polygonal (hexagonal) chambers or 'honeycomb' pits called corallites.
- Hardness
- 3-4 (calcite) or up to 7 (if silicified/replaced by quartz)
- Color
- Typically tan, gray, or white
- Luster
- Dull to earthy
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Physical properties
Hardness: 3-4 (calcite) or up to 7 (if silicified/replaced by quartz). Color: Typically tan, gray, or white. Luster: Dull to earthy. Structure: Characterized by small, polygonal (hexagonal) chambers or 'honeycomb' pits called corallites.
Formation & geological history
Formed from the skeletons of an extinct genus of tabulate corals that lived from the Late Ordovician to the Late Devonian periods (approx. 450 to 360 million years ago). They grew in warm, shallow sunlit seas.
Uses & applications
Primarily used as educational specimens, collectibles, and decorative garden or aquarium stones. In some regions, ancient reef rock is used as lime for soil or construction aggregate.
Geological facts
Favosites corals were colonial organisms. The name comes from the Latin 'favus', meaning honeycomb. Unlike modern corals, they featured horizontal internal partitions called tabulae, which supported the living polyp.
Field identification & locations
Identify in the field by looking for a small honeycomb-like grid of tiny holes on the surface of rounded stream stones or limestone outcrops. Commonly found in the Great Lakes region (USA/Canada), Ohio River Valley, and New York state. For collectors: wet the stone to see the hexagonal pattern more clearly.
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