sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Hardness: 3-4 (Mohs scale), Color: Dark grey to charcoal when wet, Luster: Dull/Earthy, Crystal Structure: Microcrystalline with visible bioclasts, Cleavage: None (conchoidal or irregular fracture)
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3-4 (Mohs scale), Color: Dark grey to charcoal when wet, Luster: Dull/Earthy, Crystal Structure: Microcrystalline with visible bioclasts, Cleavage: None (conchoidal or irregular fracture)
Formation & geological history
Formed in shallow marine environments from the accumulation of skeletal remains including crinoids, brachiopods, and bryozoans. These deposits often date back to the Paleozoic era (approx. 300-500 million years ago) and are consolidated through lithification.
Uses & applications
Used in the manufacturing of cement, as a decorative garden stone, and as aggregate for construction and roadbeds. High-quality specimens are popular for educational purposes and fossil hunting.
Geological facts
This specimen likely contains fragments of ancient marine life. Limestone covers about 10% of the Earth's total land area and is the primary rock type in which karst landscapes (caves and sinkholes) develop.
Field identification & locations
Identify in the field by checking for the presence of visible fossil fragments and its reaction to diluted hydrochloric acid (it will fizz). Commonly found in riverbeds, quarries, and outcrops within sedimentary basins.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary