sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness: 3 on Mohs scale. Color: Light grey to brownish-tan due to iron oxide staining. Luster: Dull, earthy. Structure: Microcrystalline to fine-grained. Cleavage: None (conchoidal to irregular fracture). Specific gravity: 2.5–2.7.
- Hardness
- 3 on Mohs scale
- Color
- Light grey to brownish-tan due to iron oxide staining
- Luster
- Dull, earthy
Identified More sedimentary →
Explore Limestone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3 on Mohs scale. Color: Light grey to brownish-tan due to iron oxide staining. Luster: Dull, earthy. Structure: Microcrystalline to fine-grained. Cleavage: None (conchoidal to irregular fracture). Specific gravity: 2.5–2.7.
Formation & geological history
Formed in shallow, calm, warm marine waters by the accumulation and compaction of shells, coral, algal, and fecal debris, or chemical precipitation of calcium carbonate.
Uses & applications
Widely used as a aggregate in construction, manufacturing of cement and lime, soil conditioner in agriculture, and neutralizer in chemical processing.
Geological facts
Limestone effervesces (fizzes) strongly when exposed to dilute hydrochloric acid. Over 10% of all sedimentary rocks on Earth are limestones.
Field identification & locations
Easily identified by testing with a drop of acid or vineger to observe fizzing. It is soft enough to be scratched by a steel nail. Commonly found near ancient seabed exposures and riverbeds.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary