sedimentary

Fossiliferous limestone (probable)

Bioclastic limestone, mainly calcite (CaCO₃)

AI-generated identification · may be incorrect

Gray, rough, fine-grained matrix with pale shell-like fragments and dark patches; calcite is Mohs 3, vitreous to dull, trigonal, and cleaves rhombohedrally. The image is not clear enough to confirm the fragments are fossils or identify the dark material.

Identified October 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed as carbonate sediment and shell debris accumulated in a marine setting, then compacted and cemented; its age cannot be determined from the image.

Uses & applications

Limestone is widely used for aggregate, building stone, and cement manufacture; fossil-bearing pieces are also collected and used decoratively.

Geological facts

Fossiliferous limestone preserves remains of marine organisms, though some pale fragments in this specimen could instead be mineral clasts.

Field identification & locations

Look for identifiable shells or fossils and test a fresh surface with dilute acid: calcite-rich limestone fizzes. Common worldwide in ancient marine sedimentary formations.