sedimentary

Fossiliferous limestone

Calcite-rich carbonate rock; chiefly CaCO₃ (often bioclastic limestone)

AI-generated identification · may be incorrect

Typically pale gray to cream, dull to slightly crystalline, with visible fossil fragments and calcite-rich matrix; Mohs hardness 3, poor cleavage, specific gravity about 2.3–2.7. Effervesces vigorously with dilute hydrochloric acid or strong vinegar.

Identified August 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when shells, skeletal debris, and carbonate mud accumulate in shallow marine environments, then compact and cement; specimens may range from Paleozoic to Cenozoic in age. The visible fragments suggest biological deposition rather than volcanic rock.

Uses & applications

Crushed for aggregate, road base, cement, lime, and soil conditioning; attractive fossiliferous pieces are used as décor and educational specimens. Common pieces generally have modest commercial value.

Geological facts

Fossils can include shell fragments, corals, bryozoans, or echinoids, though the image is not detailed enough for precise identification. Limestone is one of Earth’s most widespread sedimentary rocks and commonly forms karst landscapes.

Field identification & locations

Look for bedding, rounded fossil debris, low density, and acid reaction; distinguish it from concrete by natural irregular texture and fossils rather than uniform cement and aggregate. Common worldwide, especially ancient shallow-sea regions.