sedimentary
Limestone
Calcium Carbonate (CaCO3)
Hardness: 3 on the Mohs scale, Color: Varies from white, gray, yellow to brown, Luster: Earthy to dull, Crystal structure: Trigonal (as calcite), Cleavage: Perfect in three directions, Specific gravity: 2.71
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Physical properties
Hardness: 3 on the Mohs scale, Color: Varies from white, gray, yellow to brown, Luster: Earthy to dull, Crystal structure: Trigonal (as calcite), Cleavage: Perfect in three directions, Specific gravity: 2.71
Formation & geological history
Formed by the accumulation of organic remains such as shells and coral, or through the chemical precipitation of calcium carbonate from water in marine environments.
Uses & applications
Widely used in construction as aggregate, in the production of cement, as a soil conditioner in agriculture, and in the manufacturing of glass and paper.
Geological facts
Limestone often contains fossils of ancient marine organisms, providing a historical record of Earth's past environments. Famous structures like the Great Pyramid of Giza are built largely of limestone.
Field identification & locations
Can be easily identified in the field by its characteristic fizzing reaction when exposed to dilute hydrochloric acid due to the release of carbon dioxide gas.
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