sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectMohs hardness of 3; colors range from white, gray, to tan; dull to earthy luster; hexagonal crystal system when crystallized as calcite.
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Physical properties
Mohs hardness of 3; colors range from white, gray, to tan; dull to earthy luster; hexagonal crystal system when crystallized as calcite.
Formation & geological history
Formed through the accumulation of organic remains like shell and coral debris or chemical precipitation in shallow marine environments over millions of years.
Uses & applications
Widely used in construction as building stone, a primary component in cement manufacture, and in agricultural soil treatment.
Geological facts
Limestone frequently contains well-preserved fossils and forms dramatic cave systems through dissolution by acidic groundwater.
Field identification & locations
Identified easily by a vigorous fizzing reaction when cold dilute hydrochloric acid is applied due to carbon dioxide release.
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Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion
Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image
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Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
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Sandstone or Siltstone
Arenite (if sandstone)
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Sandstone
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Shale
Shale (clastic sedimentary rock)
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Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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