sedimentary

Fossiliferous limestone pebble

Calcite-rich limestone (mainly CaCO₃), containing marine shell fossils

AI-generated identification · may be incorrect

Gray, rounded, fine-grained carbonate with pale fossil and shell fragments; calcite has Mohs hardness 3, vitreous to dull luster, and trigonal crystal structure. The rock fizzes in dilute acid; the rounded shape suggests water abrasion.

Identified October 3, 2026More sedimentary →

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Physical properties

Formation & geological history

Shell material accumulated in a marine environment and was lithified into limestone; later erosion rounded it into a pebble. Its precise age cannot be determined from the image.

Uses & applications

Mostly a collector’s specimen or decorative stone; limestone is widely used for cement, aggregate, and building stone.

Geological facts

The visible pale patches appear to be fossil shell material preserved in the carbonate matrix.

Field identification & locations

Look for shell outlines or fragments and test a small inconspicuous spot with dilute acid for fizzing; fossiliferous limestone occurs in sedimentary regions worldwide. The image does not support a specific fossil or locality identification.