sedimentary
Limestone
Sedimentary rock composed primarily of Calcium Carbonate (CaCO3)
Hardness: 3 on Mohs scale; Color: Tan, beige, or light grey; Luster: Dull to earthy; Texture: Fine-grained to clastic; Cleavage: None (conchoidal to irregular fracture).
- Hardness
- 3 on Mohs scale
- Color
- Tan, beige, or light grey
- Luster
- Dull to earthy
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3 on Mohs scale; Color: Tan, beige, or light grey; Luster: Dull to earthy; Texture: Fine-grained to clastic; Cleavage: None (conchoidal to irregular fracture).
Formation & geological history
Formed primarily in marine environments from the accumulation of shell, coral, algal, and fecal debris. It can also form through the precipitation of calcium carbonate from lake or ocean water.
Uses & applications
Extensively used in construction as an aggregate, a key ingredient in cement/concrete, a soil conditioner in agriculture, and for architectural cladding.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It is most famous for forming spectacular karst landscapes, such as caves, sinkholes, and towers.
Field identification & locations
Can be identified in the field using the 'acid test'—it will effervesce (fizz) when a drop of dilute hydrochloric acid is applied. It is commonly found in areas that were once ancient sea beds.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone
Arenite
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary