sedimentary

Likely weathered limestone or calcareous sandstone

Calcite-rich carbonate rock; predominantly CaCO₃, possibly micritic limestone

AI-generated identification · may be incorrect

Pale gray-beige, dull to faintly earthy luster, fine-grained and rounded by weathering; hardness about 3 if calcitic, with poor-to-indistinct cleavage in a massive aggregate. Exact identification requires a fresh surface and acid test.

Identified August 30, 2026More sedimentary →

Explore Likely weathered limestone or calcareous sandstone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Likely formed from accumulated carbonate mud or sand that lithified during the Phanerozoic; subsequent erosion produced the smooth shape. A dilute hydrochloric-acid or vinegar fizz would support limestone, though weak reactions may occur in compact material.

Uses & applications

Common limestone is used for cement, aggregate, lime, soil treatment, and building stone; this small weathered piece has little commercial value but may be useful as a teaching or casual collecting specimen.

Geological facts

Calcite-rich limestone can fizz visibly in dilute hydrochloric acid, while sandstone generally does not unless cemented by calcite. The specimen’s porous, granular surface and lack of visible crystals favor a weathered sedimentary rock.

Field identification & locations

Common in marine sedimentary terrains worldwide, including caves, shorelines, river gravels, and quarries. Check streak, grain texture, density, and acid reaction; avoid relying on color alone because weathering alters it substantially.