sedimentary

Rounded limestone pebble

Micritic limestone, composed mainly of calcite (CaCO₃)

AI-generated identification · may be incorrect

Cream-white, dull to weakly waxy luster, fine-grained and massive, with a rounded water-worn surface. Mohs hardness 3; calcite may show weak cleavage and effervesces vigorously with dilute hydrochloric acid; specific gravity about 2.6–2.8.

Identified August 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from compacted carbonate mud or microscopic marine shells, likely deposited in a shallow-marine environment and later lithified. Its exact geological age cannot be determined from the photograph; surface rounding indicates stream, beach, or glacial transport.

Uses & applications

Common limestone is used for cement, aggregate, lime, and building stone, though this small pebble has primarily educational or decorative value.

Geological facts

The subtle porous texture and pale color are typical of micritic limestone; a concealed fossil fragment is possible but not visible here.

Field identification & locations

Common in riverbeds, beaches, karst regions, and sedimentary outcrops worldwide. Confirm with a vinegar or acid test, noting that weak vinegar may react slowly; avoid testing valuable specimens.