Rock Identifier
Fossiliferous Limestone (Calcium Carbonate (CaCO3) with Organic Inclusions) — fossil
fossil

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with Organic Inclusions

AI-generated identification · may be incorrect

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
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Physical properties

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.

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.

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Bioclastic limestone, composed chiefly of calcite (CaCO₃)

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Weathered fossil bone fragment (identification uncertain)

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