sedimentary
Limestone
Calcium Carbonate (CaCO3 / Calcite)
AI-generated identification · may be incorrectHardness: 3 on Mohs scale. Color: Light grey, off-white, beige. Luster: Dull to earthy. Texture: Fine-grained, microcrystalline, slightly rough to grainy.
- Hardness
- 3 on Mohs scale
- Color
- Light grey, off-white, beige
- Luster
- Dull to earthy
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Physical properties
Hardness: 3 on Mohs scale. Color: Light grey, off-white, beige. Luster: Dull to earthy. Texture: Fine-grained, microcrystalline, slightly rough to grainy.
Formation & geological history
Formed through the accumulation and compaction of organic debris like shells and coral, or chemical precipitation of calcium carbonate in shallow, warm marine environments over millions of years.
Uses & applications
Widely used in construction aggregate, cement manufacturing, soil neutralization in agriculture, chemical production, and as a dimension stone.
Geological facts
Limestone forms extensive karst landscapes around the world, creating vast cave systems and sinkholes. It reacts vigorously with dilute hydrochloric acid, producing carbon dioxide gas bubbles.
Field identification & locations
Identified in the field by its softness (can be scratched with a steel nail), dull earthy texture, light gray appearance, and effervescence (fissing) when exposed to a weak acid like vinegar.
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