sedimentary

Weathered fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃)

AI-generated identification · may be incorrect

Typically gray-brown, dull to earthy, fine- to medium-grained, with visible shell or fossil fragments and occasional calcite-filled cavities; Mohs hardness 3, poor cleavage, specific gravity about 2.6–2.8. The rounded shape and dark surface suggest weathering or stream abrasion.

Identified August 12, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when marine shells, skeletal debris, and carbonate mud accumulate, compact, and cement on ancient seafloors; age cannot be determined from the photograph and may range from Paleozoic to Cenozoic. Surface weathering has exposed fossil material and softened edges.

Uses & applications

Used as aggregate, cement and lime feedstock, building stone, and ornamental material; fossiliferous pieces are mainly collected for educational or decorative purposes.

Geological facts

The pale, rounded inclusion appears possibly to be a shell fragment or calcite vein rather than a separate mineral. Vinegar or dilute hydrochloric acid should produce visible fizz if the surface contains exposed calcite.

Field identification & locations

Likely found in limestone outcrops, quarries, streambeds, and coastal gravels. Confirm with acid fizz, a hardness test against a steel nail, and a close inspection for shell chambers, pores, or bedding; identification is not definitive from the image alone.