sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, conchoidal fracture, waxy to vitreous luster, and varying colors including brown, grey, and tan.
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Physical properties
Hardness of 7 on the Mohs scale, conchoidal fracture, waxy to vitreous luster, and varying colors including brown, grey, and tan.
Formation & geological history
Formed through the chemical precipitation of silica-rich fluids or accumulation of siliceous skeletal remains in marine environments over millions of years.
Uses & applications
Historically used for making stone tools and arrowheads due to its sharp conchoidal fracture; currently used in aggregate and abrasives.
Geological facts
Chert forms nodules within limestone or chalk formations and was essential for ancient human survival in creating fire and cutting tools.
Field identification & locations
Identified by its extreme hardness, waxy luster, and sharp-edged conchoidal breaks, commonly found in limestone-rich sedimentary deposits worldwide.
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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
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone
Arenite
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary