fossil

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with Organic Inclusions

Hardness: 3 on Mohs scale; Color: Gray, beige, buff, brownish-gray; Luster: Dull to earthy; Texture: Fine-grained matrix containing visible fossil molds or casts; Reaction: Effervesces readily in dilute hydrochloric acid.

Hardness: 3 on Mohs scale
Color: Gray, beige, buff, brownish-gray
Luster: Dull to earthy

Identified July 27, 2026More fossil →

Explore Fossiliferous Limestone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed in warm, shallow marine environments where carbonated skeletal fragments, shells, or organisms accumulated and were compacted and cemented over millions of years.

Uses & applications

Used in construction, as crushed stone aggregate, for lime production, architectural cladding, and as an educational or display specimen for fossil enthusiasts.

Geological facts

Limestone often preserves delicate impressions or shell casts of prehistoric marine life like brachiopods, crinoids, bivalves, or coral.

Field identification & locations

Identify by testing soft hardness with steel, checking for shell or organism outlines, and testing for acid effervescence. Commonly found in sedimentary basins and ancient seabed rock formations worldwide.

Other fossil specimens

See all

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil

Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

sedimentary

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

fossil

Fossiliferous Limestone

Limestone with embedded fossil cross-section

sedimentary

Fossiliferous Limestone

Fossiliferous Calcilutite / Biomicrite

sedimentary