sedimentary

Calcite-rich limestone

Limestone, predominantly calcium carbonate (CaCO₃), usually calcite

AI-generated identification · may be incorrect

Cream-white, dull to pearly luster, granular crystalline texture, irregular fracture, and probable Mohs hardness 3; calcite typically effervesces vigorously with dilute hydrochloric acid. Brown patches may be weathering, iron staining, or fossil/organic material.

Identified August 22, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by accumulation and compaction of marine carbonate shells, mud, or chemical calcite precipitates; age cannot be determined from the photograph and may range from Paleozoic to recent. Later recrystallization could produce a marble-like texture.

Uses & applications

Used for cement and lime manufacture, aggregate, dimension stone, soil neutralization, and architectural stone; attractive pieces may be collected but are generally not jewelry-grade.

Geological facts

Limestone is one of Earth’s most widespread sedimentary rocks and commonly preserves fossils. Acid reaction and relatively low hardness distinguish calcite-rich limestone from quartz-rich rocks.

Field identification & locations

Common worldwide, especially in former shallow-marine basins; inspect for fossils, bedding, and acid fizz, and avoid confusing it with marble, which is more uniformly crystalline. Approximate value: $1–$15 for an ordinary hand specimen, or $20–$75 if fossiliferous or unusually attractive.