sedimentary

Fossiliferous limestone

Bioclastic limestone, composed chiefly of calcite (CaCO₃) and fossil fragments

AI-generated identification · may be incorrect

Gray to tan, rough and uneven, with visible shell or fossil impressions in a fine carbonate matrix. Calcite has Mohs hardness 3, vitreous to dull luster, and rhombohedral cleavage; rock properties vary with cementation and impurities.

Identified October 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms as marine shell and skeletal debris accumulates on the seafloor and is compacted and cemented. The image alone cannot establish its geological age; fossiliferous limestone occurs from the Paleozoic to the present.

Uses & applications

Used as building and landscaping stone, aggregate, and cement or lime feedstock; attractive fossil-bearing pieces may be collected or displayed.

Geological facts

Limestone often reacts with dilute hydrochloric acid, fizzing as calcite releases carbon dioxide.

Field identification & locations

The rounded fossil-like forms suggest bioclastic limestone, though the photo is not clear enough to identify the fossils or confirm the rock type. Common in ancient marine sedimentary basins worldwide; inspect fresh surfaces for shell structure and test a small spot with dilute acid.