sedimentary
Limestone
Calcium Carbonate (CaCO3)
Hardness of 3 on the Mohs scale; color ranges from white, gray, yellow, to tan; dull to earthy luster; typically fine-grained to microcrystalline; effervesces (fizzes) when dilute hydrochloric acid is applied.
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Physical properties
Hardness of 3 on the Mohs scale; color ranges from white, gray, yellow, to tan; dull to earthy luster; typically fine-grained to microcrystalline; effervesces (fizzes) when dilute hydrochloric acid is applied.
Formation & geological history
Formed through the accumulation of skeletal fragments of marine organisms such as coral, algal, and molluscan remains, as well as chemical precipitation of calcium carbonate from water.
Uses & applications
Widely used in the construction industry as building material, an aggregate for roads, an ingredient in the manufacture of Portland cement, and in agriculture to neutralize acidic soils.
Geological facts
Limestone often contains fossils of ancient marine life. Famous architectural structures like the Great Pyramids of Giza and parts of the Empire State Building utilize limestone.
Field identification & locations
Identified by its characteristic light color, relatively soft nature, and vigorous reaction with acid. Found worldwide in sedimentary basins and ancient sea beds.
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