sedimentary
Limestone (Flagstone)
Fossiliferous Limestone (CaCO3)
Hardness: 3 on Mohs scale; Color: Tan, beige, grey; Luster: Dull to earthy; Structure: Biological sediment/clastic; Cleavage: None (conchoidal to uneven fracture); Specific Gravity: 2.5-2.7
- Hardness
- 3 on Mohs scale
- Color
- Tan, beige, 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, grey; Luster: Dull to earthy; Structure: Biological sediment/clastic; Cleavage: None (conchoidal to uneven fracture); Specific Gravity: 2.5-2.7
Formation & geological history
Formed in marine environments from the accumulation of shell, coral, algal, and fecal debris. These specific specimens likely date from the Paleozoic or Mesozoic eras and were formed through lithification of calcium carbonate sediments.
Uses & applications
Primary uses include architectural flagstone, patio paving, garden walkways, and as a component in cement production or as crushed stone for road bases.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It often contains visible fossils of ancient marine organisms, such as the small white shell fragments seen in this specimen.
Field identification & locations
Identify in the field by its softness (it can be scratched by a steel nail) and its effervescent reaction when touched with a weak acid like vinegar. Look for fossilized inclusions and bedding planes.
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