sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

AI-generated identification · may be incorrect

Tan to cream, with abundant rounded and elongate fossil fragments in a fine carbonate matrix; calcite is Mohs 3, typically has a vitreous-to-dull luster and rhombohedral cleavage. The visible fossil pieces suggest a bioclastic texture; exact fossil identification is not possible from the photo.

Identified September 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when marine shells and other skeletal debris accumulated on a seafloor, then compacted and cemented by calcium carbonate. Its age cannot be determined from appearance alone; such limestone forms in marine settings across many geological periods.

Uses & applications

Commonly used as building and decorative stone, aggregate, and a source of lime and cement; attractive fossil-rich pieces are collected or polished.

Geological facts

Fossiliferous limestone preserves evidence of ancient marine ecosystems and may contain shell, crinoid, or coral remains.

Field identification & locations

Look for recognizable fossil fragments embedded in a calcite-rich matrix; a drop of dilute acid typically fizzes, though weathering can reduce the reaction. Limestone occurs widely in ancient marine sedimentary basins worldwide.