sedimentary

Limestone

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale. Color: White, gray, yellow, or brown. Luster: Earthy to dull. Crystal structure: Hexagonal (calcite). Cleavage: Perfect in three directions. Specific gravity: 2.71.

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

Identified August 3, 2026More sedimentary →

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Physical properties

Hardness: 3 on Mohs scale. Color: White, gray, yellow, or brown. Luster: Earthy to dull. Crystal structure: Hexagonal (calcite). Cleavage: Perfect in three directions. Specific gravity: 2.71.

Formation & geological history

Formed through the accumulation of skeletal fragments of marine organisms such as coral, algal, and foraminifera, or through chemical precipitation. Geological age spans from the Precambrian to recent times.

Uses & applications

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

Geological facts

Limestone often contains fossils, which help geologists understand ancient marine environments. Famous monuments like the Great Pyramid of Giza and parts of the Empire State Building utilize limestone.

Field identification & locations

Can be identified in the field by its characteristic reaction to dilute hydrochloric acid, producing effervescence (bubbling) due to carbon dioxide release. Commonly found worldwide in sedimentary basins.