sedimentary
Fossiliferous Limestone with Brachiopod shell
Calcium carbonate (CaCO3)
Hardness: 3 (Mohs scale), Color: Creamish-white to light gray, Luster: Dull to earthy (matrix) with vitreous fossil imprints, Crystal structure: Orthorhombic or Trigonal, Cleavage: Perfect rhombohedral in calcite crystals, SG: 2.7
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3 (Mohs scale), Color: Creamish-white to light gray, Luster: Dull to earthy (matrix) with vitreous fossil imprints, Crystal structure: Orthorhombic or Trigonal, Cleavage: Perfect rhombohedral in calcite crystals, SG: 2.7
Formation & geological history
Formed through the accumulation of organic debris such as shells, coral, and algal remains in shallow, warm marine environments. Often dates from the Paleozoic to Mesozoic eras.
Uses & applications
Used primarily for geological education, fossil collecting, and occasionally as a source of lime or in construction. This specific small sample is mainly a collector's item.
Geological facts
Limestone covers about 10 percent of the total land area of the Earth. The fossils within it are valuable indicators of past climate and environmental conditions.
Field identification & locations
Identify by looking for shell imprints or rib-like structures (brachiopod hinges) in a soft, easily scratched matrix that fizzles when exposed to weak acid (HCl). Found globally in 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