sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness of 3 on the Mohs scale, typically gray, white, or tan in color, 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 gray, white, or tan in color, with a dull to earthy luster and fine-grained crystal structure.
Formation & geological history
Formed through the accumulation and compaction of organic remains like shells and coral, or chemical precipitation in marine environments over millions of years.
Uses & applications
Widely used in the construction industry for crushed stone, cement production, and as a dimensional building stone.
Geological facts
Limestone frequently contains well-preserved fossils and dissolves slowly in acidic water, creating dramatic cave systems and karst topography.
Field identification & locations
Easily identified by its characteristic effervescence when exposed to dilute hydrochloric acid; found globally in ancient marine sedimentary basins.
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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