sedimentary

Rounded limestone pebble

Micritic limestone, primarily calcite (CaCO₃)

AI-generated identification · may be incorrect

Light cream, fine-grained, matte to weakly waxy luster, with faint fossil or vein-like markings; calcite has Mohs hardness 3, rhombohedral cleavage, and specific gravity about 2.7. Its smooth shape indicates water abrasion, and it may fizz with dilute hydrochloric acid or strong vinegar if freshly exposed.

Identified September 16, 2026More sedimentary →

Explore Rounded limestone pebble 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

Formed from compacted and cemented carbonate mud or microscopic marine shells, commonly during the Paleozoic–Cenozoic eras; the pebble was later eroded and rounded in a stream, beach, or gravel deposit.

Uses & applications

Used for cement, lime, aggregate, building stone, and decorative landscaping; attractive polished pieces may be collected but are generally low-value.

Geological facts

The surface appears strongly weathered or lightly polished, obscuring its original texture. Cream limestone can resemble marble, but limestone is usually softer and may react visibly with acid.

Field identification & locations

Common in karst and sedimentary regions, river gravels, beaches, and crushed-stone deposits. Look for acid effervescence, powdery streak, softness relative to steel, and possible fossil fragments; avoid mistaking concrete for limestone by checking for uniform artificial aggregate.