sedimentary
Limestone (Brecciated/Recrystallized)
Calcium Carbonate (CaCO3)
Hardness: 3 on Mohs scale; Color: Gray to brownish-gray with earthy inclusions; Luster: Dull to sub-vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: Perfect rhombohedral in calcite grains; Specific Gravity: 2.5-2.7
- Hardness
- 3 on Mohs scale
- Color
- Gray to brownish-gray with earthy inclusions
- Luster
- Dull to sub-vitreous
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 brownish-gray with earthy inclusions; Luster: Dull to sub-vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: Perfect rhombohedral in calcite grains; Specific Gravity: 2.5-2.7
Formation & geological history
Formed through the accumulation of shell, coral, algal, and fecal debris in marine environments. This specific specimen appears to have undergone secondary weathering or brecciation, possibly during tectonic movement or through chemical dissolution (karst processes) followed by cementation.
Uses & applications
Primary source of lime for cement, used extensively in construction as aggregate, architectural stone, and as a soil conditioner in agriculture. Pure forms are used in the manufacturing of paper, glass, and plastic.
Geological facts
Limestone occupies about 10% of the total volume of all sedimentary rocks. It is the primary host rock for most of the world's cave systems due to its solubility in slightly acidic water.
Field identification & locations
Identification in the field is best achieved using a 10% hydrochloric acid 'fizz test' (limestone will effervesce). Look for visible fossils or a gritty, crystalline texture. It is ubiquitous globally particularly in ancient seabed regions.
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