sedimentary
Limestone
Calcium Carbonate (CaCO3)
Hardness of 3 on the Mohs scale, colors range from white, gray, yellow to brown, dull to earthy luster, fine-grained to coarse crystal structure, good cleavage in three directions (rhombohedral), specific gravity around 2.7.
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Physical properties
Hardness of 3 on the Mohs scale, colors range from white, gray, yellow to brown, dull to earthy luster, fine-grained to coarse crystal structure, good cleavage in three directions (rhombohedral), specific gravity around 2.7.
Formation & geological history
Formed through the accumulation and compaction of organic remains like shell, coral, and algal debris, or through the chemical precipitation of calcium carbonate from water in marine environments.
Uses & applications
Widely used in the construction industry for crushed stone in road base, as a primary component in manufacturing Portland cement, in agriculture for neutralizing acidic soils, and in the production of lime and glass.
Geological facts
Limestone often contains fossils of ancient marine organisms and is soluble in weak acidic solutions, which leads to the formation of spectacular cave systems and karst topography.
Field identification & locations
Can be easily identified in the field by applying a drop of dilute hydrochloric acid, which will cause it to fizz and effervesce due to the release of carbon dioxide gas. Found globally in sedimentary basins.
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