Rock Identifier
Fossil Coral (Rugosa or Tabulata coral fossil (Calcium carbonate, CaCO3)) — fossil
fossil

Fossil Coral

Rugosa or Tabulata coral fossil (Calcium carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness of 3-4 on the Mohs scale, colors ranging from grey and brown to white, vitreous to dull luster, hexagonal or radial crystal-like internal corallite structures.

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Physical properties

Hardness of 3-4 on the Mohs scale, colors ranging from grey and brown to white, vitreous to dull luster, hexagonal or radial crystal-like internal corallite structures.

Formation & geological history

Formed through permineralization where ancient coral skeletons were replaced by minerals like silica or calcite in shallow Paleozoic marine environments.

Uses & applications

Used in decorative jewelry, lapidary art, and as educational or display specimens for fossil collectors.

Geological facts

Many fossil corals found inland were once part of vast tropical reef systems millions of years ago during the Paleozoic era.

Field identification & locations

Identify by distinctive star-like patterns, honeycomb textures, or parallel tube structures on weathered surfaces; commonly found in limestone-rich regions.

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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) — fossil

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
Porous limestone pebble (Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image) — sedimentary

Porous limestone pebble

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

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)

fossil