sedimentary

Rounded tan stone, likely limestone

Probably micritic limestone (calcite, CaCO₃); identification is uncertain from the image alone

AI-generated identification · may be incorrect

Opaque, tan, dull to slightly earthy surface, and rounded; hardness and crystal structure cannot be determined visually. Limestone is typically Mohs 3 and reacts with dilute acid, though this specimen’s texture is not clear enough to confirm.

Identified October 13, 2026More sedimentary →

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Physical properties

Formation & geological history

If limestone, it formed from accumulated carbonate mud or shell material that lithified in a marine or lake setting; its age and subsequent rounding are unknown.

Uses & applications

Common limestone is used for aggregate, cement, and building stone; this rounded piece is mainly suitable for display or collecting.

Geological facts

The smooth, rounded shape suggests prolonged transport or natural abrasion, but could also result from deliberate shaping.

Field identification & locations

Look for calcite grains or fossils and test a hidden spot with dilute acid for fizzing; limestone occurs worldwide. The photo alone cannot securely distinguish it from other tan sedimentary rocks.