sedimentary
Limestone
Calcium carbonate (CaCO3)
AI-generated identification · may be incorrectHardness of 3 on Mohs scale, typically white, gray, or tan in color with an earthy to dull luster. Composed mainly of calcite and aragonite crystals with a fine-grained or granular structure.
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Physical properties
Hardness of 3 on Mohs scale, typically white, gray, or tan in color with an earthy to dull luster. Composed mainly of calcite and aragonite crystals with a fine-grained or granular structure.
Formation & geological history
Formed through the accumulation and compaction of organic remains like shells, coral, and algae, or through chemical precipitation in shallow marine environments over millions of years.
Uses & applications
Extensively used in construction as crushed stone for road base, as a primary component in the manufacture of Portland cement, and in agricultural soil conditioning.
Geological facts
Limestone frequently contains well-preserved fossils of ancient marine organisms and is prone to forming caves and sinkholes via dissolution by acidic groundwater.
Field identification & locations
Identified in the field by its characteristic reaction to dilute hydrochloric acid, which causes it to effervesce vigorously. Commonly found in sedimentary basins and ancient sea beds worldwide.
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