fossil

Fossilized Coral

Rugose coral / Tabulate coral (Calcium carbonate, CaCO3)

Hardness on Mohs scale is typically 3 (calcite); color varies from white and gray to brown or tan; luster is dull to vitreous; crystal structure is hexagonal (calcite) or orthorhombic (aragonite); distinctive internal radiating or honeycomb-like coral structures visible upon close inspection.

Identified July 30, 2026More fossil →

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Physical properties

Formation & geological history

Formed in ancient shallow marine environments where coral skeletons were buried by sediment and underwent permineralization, replacing the original organic structure with minerals like calcite or silica over millions of years (often Paleozoic era, around 250 to 500 million years ago).

Uses & applications

Used primarily as decorative items, lapidary work, jewelry, and as educational or collectible specimens for fossil enthusiasts.

Geological facts

Many fossil corals found in inland areas indicate that the region was once covered by ancient shallow warm-water seas.

Field identification & locations

Can be identified in the field by looking for distinctive patterns such as tiny tubes (tabulate) or horn-shaped segments with radiating septa (rugose) embedded in limestone matrix.

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Sedimentary bedrock formation (variable composition)

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Crinoid Stem Fossils (Indian Beads / St. Cuthbert's Beads)

Crinoid columnal ossicles (phylum Echinodermata)

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Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

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Fossiliferous Limestone

Limestone with embedded fossil cross-section

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