sedimentary
Limestone
Calcareous sedimentary rock (CaCO3)
Hardness: 3 on Mohs scale; Color: Gray, white, tan, or yellowish; Luster: Earthy to dull; Crystal structure: Microcrystalline or fine-grained calcite; Cleavage: None distinct in hand specimen; Specific gravity: 2.7 to 2.9
- Hardness
- 3 on Mohs scale
- Color
- Gray, white, tan, or yellowish
- Luster
- Earthy to dull
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Physical properties
Hardness: 3 on Mohs scale; Color: Gray, white, tan, or yellowish; Luster: Earthy to dull; Crystal structure: Microcrystalline or fine-grained calcite; Cleavage: None distinct in hand specimen; Specific gravity: 2.7 to 2.9
Formation & geological history
Formed through the accumulation of skeletal fragments of marine organisms such as coral, algal, and foraminifera, or through the chemical precipitation of calcium carbonate from water.
Uses & applications
Widely used in construction (aggregate for concrete, road base), manufacturing of cement, agricultural soil conditioning, and dimensional stone.
Geological facts
Limestone can host extensive cave systems due to its solubility in slightly acidic groundwater. It often contains marine fossils.
Field identification & locations
Commonly found in sedimentary basins worldwide. It effervesces (fizzes) when a drop of weak hydrochloric acid or vinegar is applied.
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