sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically brown, grey, or white in color.
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Physical properties
Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically brown, grey, or white in color.
Formation & geological history
Formed by the chemical precipitation of silica from aqueous solutions or the accumulation of siliceous skeletal remains of marine organisms over millions of years.
Uses & applications
Historically used by early humans for making stone tools and weapons due to its sharp conchoidal fracture.
Geological facts
Chert that is dark or black in color is often specifically referred to as flint. It is extremely durable and resistant to weathering.
Field identification & locations
Identified by its hard, glass-like scratch on steel and distinctive conchoidal breakage pattern; found globally in limestone 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