sedimentary

Rounded limestone pebble

Micritic limestone, primarily calcite (CaCO₃)

AI-generated identification · may be incorrect

Pale cream to white, dull-to-waxy luster, fine-grained and smoothly water-worn; Mohs hardness 3, with indistinct cleavage and specific gravity about 2.7. Likely contains small fossil or shell fragments and should effervesce strongly in dilute hydrochloric acid.

Identified August 30, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from compacted carbonate mud and/or skeletal debris, later lithified into limestone; its rounded shape indicates transport by water or shoreline abrasion. Precise geological age cannot be determined from the photograph.

Uses & applications

Used widely as aggregate, cement and lime feedstock, building stone, and landscaping material; attractive pieces may be polished or collected. This small common pebble has little commercial value.

Geological facts

The visible tan flecks may be fossil fragments, iron staining, or weathered inclusions. Limestone commonly dissolves in mildly acidic rainwater, producing caves, karst landscapes, and sinkholes.

Field identification & locations

Common in limestone regions, riverbeds, beaches, and glacial deposits. Confirm with an acid test, scratch test against a copper coin or steel, and close inspection for fossils; avoid acid if preservation matters.