sedimentary

Limestone

Calcareous sedimentary rock (CaCO3)

Hardness: 3 on the Mohs scale. Color: Tan, beige, gray, or white. Luster: Earthy to dull. Crystal structure: Microcrystalline or fine-grained. Cleavage: None distinct. Specific gravity: 2.7 to 2.9.

Hardness: 3 on the Mohs scale
Color: Tan, beige, gray, or white
Luster: Earthy to dull

Identified August 7, 2026More sedimentary →

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Physical properties

Hardness: 3 on the Mohs scale. Color: Tan, beige, gray, or white. Luster: Earthy to dull. Crystal structure: Microcrystalline or fine-grained. Cleavage: None distinct. Specific gravity: 2.7 to 2.9.

Formation & geological history

Formed in shallow marine environments through the accumulation of shell, coral, algal, and fecal debris, or by the chemical precipitation of calcium carbonate from water. Geologically ranges from Precambrian to recent.

Uses & applications

Widely used in construction (as aggregate for road base and concrete), manufacturing of cement, lime production, agriculture (soil conditioning), and as a building stone.

Geological facts

Limestone often contains fossils of ancient marine organisms. Famous monuments built from limestone include the Great Pyramid of Giza and the Parthenon in Athens.

Field identification & locations

Can be easily identified in the field by its characteristic effervescence (fizzing) when a drop of weak hydrochloric acid or vinegar is applied due to the release of carbon dioxide. Commonly found in sedimentary basins worldwide.