sedimentary

Light-colored carbonate pebble, likely limestone

Limestone; predominantly calcite (CaCO₃), possibly micritic or fossiliferous

AI-generated identification · may be incorrect

Small rounded, cream-white pebble with dull to slightly sugary luster and fine-grained texture; calcite hardness is 3 Mohs, with indistinct cleavage and specific gravity about 2.7. Exact mineral identity is uncertain from the photograph alone.

Identified September 18, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed from compacted carbonate mud or shell debris in a shallow marine environment, commonly during the Paleozoic–Cenozoic; rounding indicates later transport by water. It may also be a piece of dolostone or weathered concrete, though its appearance favors natural carbonate rock.

Uses & applications

Common limestone is used for aggregate, cement, lime, building stone, and soil treatment; small ordinary pebbles have little commercial or jewelry value.

Geological facts

A drop of dilute hydrochloric acid or strong vinegar should fizz noticeably if calcite-rich, though dolomite reacts weakly and surface coatings can obscure the test.

Field identification & locations

Common in river gravel, beaches, karst regions, and sedimentary basins worldwide; inspect for fossils, acid reaction, and a white streak. The image does not show diagnostic fossils or crystal structure.