sedimentary
Chert
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and colors ranging from gray, brown, to dark green.
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Physical properties
Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and colors ranging from gray, brown, to dark green.
Formation & geological history
Formed via the accumulation of siliceous microfossils or the replacement of limestone by silica-rich groundwater in marine environments.
Uses & applications
Historically used for making stone tools, arrowheads, and spark strikers, and occasionally as a decorative or lapidary stone.
Geological facts
Chert breaks with extremely sharp edges, making it ideal for ancient weaponry and cutting tools worldwide.
Field identification & locations
Identify by its hard conchoidal fracture and waxy appearance; commonly found embedded in limestone or chalk formations.
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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