Rock Identifier
Fossil coral (polished coral fossil) (Likely colonial rugose coral; fossilized calcium carbonate, chiefly calcite (CaCO₃)) — fossil
fossil

Fossil coral (polished coral fossil)

Likely colonial rugose coral; fossilized calcium carbonate, chiefly calcite (CaCO₃)

AI-generated identification · may be incorrect

Pale beige-gray, polished surface with radiating starburst corallite patterns; calcite hardness about 3, typically nonmetallic luster. Exact species and composition cannot be confirmed from the photo.

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Physical properties

Pale beige-gray, polished surface with radiating starburst corallite patterns; calcite hardness about 3, typically nonmetallic luster. Exact species and composition cannot be confirmed from the photo.

Formation & geological history

Ancient coral skeletons were buried in marine sediment and mineralized, commonly during the Paleozoic; age and locality are not identifiable from the image.

Uses & applications

Collected as a fossil and used in decorative objects and jewelry; not typically a major construction material.

Geological facts

The repeated radial patterns are coral corallites, the skeletal cups of individual polyps, preserved within a colony.

Field identification & locations

Look for repeated star-shaped or circular corallite structures across a stone surface; fossils of this appearance occur in many sedimentary formations worldwide. The photo does not establish a specific locality.

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Probable fossil-bearing rock or mineral concretion

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Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

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Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

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Fossiliferous limestone (likely a crinoidal or shell-fragment limestone) (Bioclastic limestone, composed chiefly of calcite (CaCO₃)) — sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

sedimentary
Fossil oyster shell (Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)) — fossil

Fossil oyster shell

Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)

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Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image

fossil