sedimentary

Limestone

Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Light gray, tan, yellowish, or white; Luster: Earthy to sub-vitreous; Crystal structure: Trigonal (as calcite); Cleavage: Perfect rhombohedral; Specific gravity: 2.71

Hardness: 3 on Mohs scale
Color: Light gray, tan, yellowish, or white
Luster: Earthy to sub-vitreous

Identified August 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of skeletal fragments of marine organisms such as coral, algal, and foraminifera, as well as the chemical precipitation of calcium carbonate from water.

Uses & applications

Widely used in construction as building stone, aggregate for roads, production of quicklime, cement manufacture, and agricultural soil treatment.

Geological facts

Limestone often contains fossils of ancient marine life and can dissolve in mildly acidic water, creating spectacular cave systems and karst topography.

Field identification & locations

Easily identified by its reaction to dilute hydrochloric acid, which causes it to effervesce (fizz) due to the release of carbon dioxide gas. Commonly found in sedimentary basins worldwide.