sedimentary
Fossilized Favosites (Honeycomb Coral)
Favosites (extinct genus of tabulate coral)
Hardness: 3-4 (calcite-based). Color: tan, grey, or white. Luster: dull to earthy. Structure: hexagonal, tube-like chambers (corallites) resembling a honeycomb. Cleavage: none (replaced by silica or calcite).
- Hardness
- 3-4 (calcite-based)
- Color
- tan, grey, or white
- Luster
- dull to earthy
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Physical properties
Hardness: 3-4 (calcite-based). Color: tan, grey, or white. Luster: dull to earthy. Structure: hexagonal, tube-like chambers (corallites) resembling a honeycomb. Cleavage: none (replaced by silica or calcite).
Formation & geological history
Formed through the petrification of ancient coral reefs during the Silurian and Devonian periods (approx. 360-430 million years ago) in warm, shallow seas.
Uses & applications
Used primarily as decorative collector specimens, educational fossils, and sometimes in lapidary work for jewelry if silicified (Petoskey-like stones).
Geological facts
These are known as 'Honeycomb Corals' due to their geometric pattern. They are extinct corals that lived long before dinosaurs, providing evidence of ancient seawater levels and temperatures.
Field identification & locations
Identify by looking for a repeating hexagonal grid pattern on the rock surface. Commonly found in the Great Lakes region of North America and areas with exposed Paleozoic limestone.
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