sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness: 3 (Mohs scale), Color: light gray to tan, Luster: dull to earthy, Structure: fine-grained, Cleavage: varies by calcite content, Specific Gravity: 2.5-2.7
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Physical properties
Hardness: 3 (Mohs scale), Color: light gray to tan, Luster: dull to earthy, Structure: fine-grained, Cleavage: varies by calcite content, Specific Gravity: 2.5-2.7
Formation & geological history
Formed primarily from the accumulation of shell, coral, algal, and fecal debris in marine environments. It can also be precipitates from calcium-rich water.
Uses & applications
Extensively used in construction as aggregate, in the manufacture of cement, as a soil conditioner in agriculture, and as a flux in steel making.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It is the primary rock found in karst landscapes where caves and sinkholes are common.
Field identification & locations
Identify in the field by checking for an effervescent reaction (fizzing) when exposed to a drop of dilute hydrochloric acid. Commonly found in quarries and road cuts.
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