sedimentary
Limestone
Sedimentary Rock (Primarily Calcium Carbonate, CaCO3)
Hardness of 3 on the Mohs scale, color typically ranges from white, tan, gray to brown, dull to earthy luster, fine-grained to coarse crystalline structure, good cleavage depending on calcite content, specific gravity around 2.7.
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Physical properties
Hardness of 3 on the Mohs scale, color typically ranges from white, tan, gray to brown, dull to earthy luster, fine-grained to coarse crystalline structure, good cleavage depending on calcite content, specific gravity around 2.7.
Formation & geological history
Formed through the accumulation of skeletal fragments of marine organisms such as coral, algal, and foraminifera, or through chemical precipitation of calcium carbonate from water, commonly in shallow marine environments over millions of years.
Uses & applications
Widely used in construction as building stone and as a primary raw material for the manufacture of Portland cement, crushed stone for road base, and agricultural soil treatment.
Geological facts
Limestone often contains well-preserved 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 reaction with dilute hydrochloric acid, producing effervescence (bubbling) due to carbon dioxide release. Commonly found in sedimentary basins worldwide.
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