sedimentary
Limestone
Sedimentary rock composed primarily of Calcium Carbonate (CaCO3)
Hardness: 3 on Mohs scale; Color: light gray to off-white; Luster: dull to earthy; Texture: fine-grained; Cleavage: none (conchoidal fracture); reacts to dilute hydrochloric acid.
- Hardness
- 3 on Mohs scale
- Color
- light gray to off-white
- Luster
- dull to earthy
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Physical properties
Hardness: 3 on Mohs scale; Color: light gray to off-white; Luster: dull to earthy; Texture: fine-grained; Cleavage: none (conchoidal fracture); reacts to dilute hydrochloric acid.
Formation & geological history
Formed primarily in marine environments through the accumulation of shell, coral, algal, and fecal debris. It can also form through chemical precipitation from lake or ocean waters.
Uses & applications
Extensively used in construction, road base, cement manufacturing, as a soil conditioner in agriculture, and for architectural cladding.
Geological facts
Limestone is the primary stone used in the Great Pyramids of Giza. It is also the most common host rock for vast cave systems due to its solubility in slightly acidic groundwater.
Field identification & locations
Identify in the field by its light color and its effervescence (fizzing) when exposed to a drop of acid like vinegar or HCl. Often contains small fossils.
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