sedimentary

Limestone

Calcareous sedimentary rock (CaCO3)

Hardness: 3 on the Mohs scale; Color: White, gray, yellow, or tan; Luster: Earthy to dull; Crystal structure: Microcrystalline or fine-grained calcite; Cleavage: None distinct in rock form; Specific gravity: 2.7 to 2.9

Hardness: 3 on the Mohs scale
Color: White, gray, yellow, or tan
Luster: Earthy to dull

Identified July 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and compaction of organic remains such as shells, coral, and algal debris, or through the chemical precipitation of calcium carbonate from water in marine environments, spanning various geological ages from the Precambrian to present.

Uses & applications

Widely used in the production of cement, crushed stone for road construction, agricultural lime, building stone, and as a raw material in the manufacture of glass and paper.

Geological facts

Limestone often contains well-preserved fossils and forms dramatic landscapes characterized by caves, sinkholes, and underground drainage systems known as karst topography.

Field identification & locations

Can be easily identified in the field by its characteristic reaction to hydrochloric acid, producing effervescence (fizzing) due to the release of carbon dioxide from calcium carbonate.