sedimentary
Favosites (Honeycomb Coral Fossil)
Favosites sp. (Phylum Cnidaria, Order Tabulata)
Hardness: 3-4 (Calcite composition); Color: Tan, gray, or brown; Luster: Dull to earthy; Crystal structure: Hexagonal honeycomb-like tubes (corallites); Cleavage: None (fossilized structure).
- Hardness
- 3-4 (Calcite composition)
- Color
- Tan, gray, or brown
- Luster
- Dull to earthy
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Physical properties
Hardness: 3-4 (Calcite composition); Color: Tan, gray, or brown; Luster: Dull to earthy; Crystal structure: Hexagonal honeycomb-like tubes (corallites); Cleavage: None (fossilized structure).
Formation & geological history
Formed in warm, shallow marine environments during the Ordovician to Devonian periods (approx. 488 to 359 million years ago). The coral polyps built calcium carbonate skeletons that were buried in sediment and lithified over time.
Uses & applications
Used primarily as educational specimens, for paleontological research, as decorative pieces in collections, and sometimes in lapidary work (jewelry cabochons) when silicified.
Geological facts
Known as 'Honeycomb Coral' because of its unique appearance; these were colonial corals that lacked the radial symmetry (septa) found in modern corals. They went extinct during the Permian-Triassic extinction event.
Field identification & locations
Identify by looking for a characteristic hexagonal 'honeycomb' grid pattern on the surface. Commonly found in Paleozoic limestone deposits, particularly in the Great Lakes region of North America and parts of Europe. Field identification involves checking for the distinct tabulae (horizontal cross-walls) within the tubes.
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