sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness: 3 (Mohs scale), Color: tan, grey, or yellowish. Luster: dull/earthy. Crystal structure: Trigonal (microcrystalline). Will fizz with weak acid.
- Hardness
- 3 (Mohs scale), Color: tan, grey, or yellowish
- Color
- tan, grey, or yellowish
- Luster
- dull/earthy
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Physical properties
Hardness: 3 (Mohs scale), Color: tan, grey, or yellowish. Luster: dull/earthy. Crystal structure: Trigonal (microcrystalline). Will fizz with weak acid.
Formation & geological history
Formed in marine environments through the accumulation of shell, coral, algal, and fecal debris. Most common in shallow, warm sea waters.
Uses & applications
Used as a major building material, in the manufacture of cement, as an aggregate for road bases, and for neutralizing acidic soils.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It is the primary rock type hosting spectacular cave systems like Mammoth Cave.
Field identification & locations
Identify in the field by its softness relative to steel and its reaction (effervescence) when exposed to a drop of vinegar or diluted hydrochloric acid.
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