sedimentary
Limestone (Fossiliferous)
Calcium Carbonate (CaCO3)
Hardness: 3 on Mohs scale; Color: Gray to tan; Luster: Dull/Earthy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal; Specific Gravity: 2.3–2.7
- Hardness
- 3 on Mohs scale
- Color
- Gray to tan
- Luster
- Dull/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: Gray to tan; Luster: Dull/Earthy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal; Specific Gravity: 2.3–2.7
Formation & geological history
Formed in marine environments from the accumulation of shell, coral, algal, and fecal debris. It can be millions of years old, often dating from the Paleozoic or Mesozoic eras.
Uses & applications
Used primarily in construction (crushed stone), cement manufacturing, soil conditioning in agriculture, and as a source of lime.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. When it contains visible fossils, as seen in the texture here, it is referred to as fossiliferous limestone.
Field identification & locations
Identify in the field by its reaction (fizzing) to a drop of dilute hydrochloric acid. Commonly found in quarries and surface outcrops in areas once covered by ancient seas.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary