fossil

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with marine fossils

Hardness: 3 on Mohs scale; Color: Tan, beige, light brown, yellow-grey; Luster: Dull, earthy; Texture: Rough, granular with visible shell/fossil fragments; Cleavage: None (conchoidal to uneven fracture).

Hardness: 3 on Mohs scale
Color: Tan, beige, light brown, yellow-grey
Luster: Dull, earthy

Identified July 25, 2026More fossil →

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Physical properties

Formation & geological history

Formed in warm, shallow marine environments through the accumulation and compaction of organic debris such as shell fragments, coral, and calcium carbonate precipitate.

Uses & applications

Used in construction, soil conditioning (agricultural lime), cement manufacturing, and collected by hobbyists for fossil content.

Geological facts

Fossiliferous limestones often contain fossilized remains of ancient sea creatures like brachiopods, crinoids, bryozoans, and mollusks dating back hundreds of millions of years.

Field identification & locations

Can be identified by testing with weak acid (dilute HCl), which causes it to effervesce briskly due to calcite content, and by observing visible fossil structures on the surface.

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Phylum Echinodermata, Class Crinoidea

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Sedimentary bedrock formation (variable composition)

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Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

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Fossiliferous Limestone

Fossiliferous Calcilutite / Biomicrite

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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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