sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness of 3 on the Mohs scale, typically pale yellow, white, or gray, with a dull to earthy luster and fine-grained crystal structure.
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Physical properties
Hardness of 3 on the Mohs scale, typically pale yellow, white, or gray, with a dull to earthy luster and fine-grained crystal structure.
Formation & geological history
Formed from the accumulation of skeletal fragments of marine organisms like coral, algal, and mollusks in shallow tropical marine environments over millions of years.
Uses & applications
Widely used in the construction industry for making cement, as aggregate for road bases, and in agricultural soil conditioning.
Geological facts
Limestone often contains well-preserved fossils and forms dramatic cave systems through chemical weathering by slightly acidic groundwater.
Field identification & locations
Identified easily by its characteristic effervescence when exposed to dilute hydrochloric acid; found globally in sedimentary basins and ancient sea beds.
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Other sedimentary specimens
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
fossil
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary