sedimentary
Chert
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy or vitreous luster, conchoidal fracture, and typically gray, white, or brown in color.
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Physical properties
Hardness of 7 on the Mohs scale, waxy or vitreous luster, conchoidal fracture, and typically gray, white, or brown in color.
Formation & geological history
Formed via the chemical precipitation of silica from aqueous solutions or the accumulation of siliceous skeletal remains of marine organisms in deep-sea environments.
Uses & applications
Historically used for making sharp stone tools and weapons due to its conchoidal fracture; occasionally used in decorative landscaping and lapidary work.
Geological facts
Chert varieties include flint, jasper, and chalcedony. It was extensively used by prehistoric humans for arrowheads and fire-starting.
Field identification & locations
Identified easily by its extreme hardness, scratch test on glass, and smooth conchoidal fracture. Found worldwide within limestone and 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