sedimentary

Fossiliferous limestone pebble

Calcite-rich limestone (CaCO₃), containing weathered shell or crinoid fragments

AI-generated identification · may be incorrect

Gray-green, fine-grained, dull to subtly granular surface with cream fossil fragments; calcite hardness 3, typically non-cleaved massive texture, and specific gravity about 2.6–2.7. It should fizz with dilute hydrochloric acid or strong vinegar if exposed calcite is present.

Identified September 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from accumulated carbonate mud and marine biological debris, later lithified; the exact geological age cannot be determined from the photograph, but such limestones range from Paleozoic to Cenozoic. The rounded shape indicates stream, beach, or glacial transport.

Uses & applications

Used as aggregate, cement and lime feedstock, dimension stone, and educational or decorative fossil material; this small pebble has little industrial value.

Geological facts

The cream patches are likely shell fragments, crinoid debris, or veins rather than metallic minerals. Fossil identification requires a close view of their shapes and internal structure.

Field identification & locations

Common in former shallow-marine limestone regions and gravel deposits. Look for acid effervescence, carbonate softness, and identifiable fossil textures; avoid relying on color alone.