sedimentary

Honeycomb Coral Fossil

Favosites (extinct genus of tabulate coral)

Hardness: 3-4 (calcite) to 7 (if silicified); Color: Tan, gray, or brown; Luster: Dull to waxy; Structure: Polygonal or hexagonal 'cells' (corallites) resembling a honeycomb; Composition: Calcium carbonate or Silica replacement.

Hardness: 3-4 (calcite) to 7 (if silicified)
Color: Tan, gray, or brown
Luster: Dull to waxy

Identified March 20, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in warm, shallow marine environments during the Ordivician to Devonian periods (approx. 488 to 359 million years ago). These corals grew in massive colonies on ancient reefs.

Uses & applications

Decorative display pieces, educational geological specimens, jewelry (when silicified/petrified), and used as biological indicators to date surrounding rock strata.

Geological facts

Favosites are known as 'tabulate' corals because their tubes are divided by horizontal plates called tabulae. They were major reef builders before the Permian mass extinction wiped them out.

Field identification & locations

Look for the distinct 'honeycomb' pattern of small holes or tubes. Found globally in areas with ancient seabed exposure, such as the Great Lakes region (USA) and diverse limestone outcrops. Collectors should look for specimens with well-defined hexagonal walls.

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