sedimentary
Favosite Fossil (Calyx or Rugose Coral)
Favosites (Extinct Tabulate Coral)
Hardness: 3-4 (Calcite-based), Color: Gray, Brown, or Tan, Luster: Dull/Earthy, Structure: Hexagonal or honeycomb pattern of small pores (corallites), Specific Gravity: ~2.7
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Physical properties
Hardness: 3-4 (Calcite-based), Color: Gray, Brown, or Tan, Luster: Dull/Earthy, Structure: Hexagonal or honeycomb pattern of small pores (corallites), Specific Gravity: ~2.7
Formation & geological history
Formed in warm, shallow marine environments during the Silurian and Devonian periods (approx. 350-430 million years ago) through the mineralization of coral colonies.
Uses & applications
Primarily for geological study, education, and fossil collecting. Polished specimens are sometimes used as decorative stones or in jewelry.
Geological facts
Commonly known as 'Honeycomb Coral' because the cross-sections of the coral tubes resemble a bee's honeycomb. These reefs were once as massive as modern coral reefs.
Field identification & locations
Look for a repeating geometric pattern of small pits or 'cells' on the surface of a water-worn stone, common in the Great Lakes region (e.g., Petoskey area).
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