sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness of 3 on the Mohs scale, colors range from white, gray, tan, to yellow, dull to earthy luster, rhombohedral cleavage, specific gravity of 2.7.
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Physical properties
Hardness of 3 on the Mohs scale, colors range from white, gray, tan, to yellow, dull to earthy luster, rhombohedral cleavage, specific gravity of 2.7.
Formation & geological history
Formed through the accumulation of skeletal fragments from marine organisms like coral, mollusks, and foraminifera, or by chemical precipitation from water, typically in shallow marine environments over millions of years.
Uses & applications
Widely used in construction as building stone, a primary component of Portland cement, crushed stone for road bases, agricultural soil conditioning, and in the production of lime and glass.
Geological facts
Limestone often contains fossils of ancient sea life. Famous structures like the Great Pyramids of Giza and parts of the Empire State Building utilize limestone.
Field identification & locations
Identified by its characteristic reaction to dilute hydrochloric acid, producing effervescence (fizzing). Found worldwide in sedimentary basins, particularly in regions that were once ancient shallow seas.
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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