sedimentary

Likely limestone (calcareous rock fragment)

Limestone, composed chiefly of calcite (CaCO₃); exact identification is uncertain from the photograph.

AI-generated identification · may be incorrect

Pale cream to white, dull and fine-grained with a rough, crumbly-looking surface. Calcite has Mohs hardness 3, trigonal crystal structure, and rhombohedral cleavage; the rock’s density and texture vary with impurities and porosity.

Identified October 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Typically forms as calcite-rich shells and skeletal debris accumulate on seafloors and lithify; limestone ranges from recent deposits to rocks billions of years old.

Uses & applications

Used for cement and lime manufacture, building stone, aggregate, and soil treatment; this small rough fragment has little commercial value.

Geological facts

Calcite-rich limestone fizzes when exposed to dilute acid, a useful field test.

Field identification & locations

Common in former marine environments worldwide. A drop of vinegar may produce a weak fizz; a harder rock that does not fizz could instead be another pale stone, such as quartz-rich material.