sedimentary
Chert
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 7 on Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to dark brown.
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Physical properties
Hardness of 7 on Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to dark brown.
Formation & geological history
Formed via the precipitation of silica from aqueous solutions or the accumulation of siliceous microfossil skeletons in marine environments over millions of years.
Uses & applications
Historically used for making stone tools and arrowheads due to its sharp conchoidal fracture; occasionally used for decorative landscaping and lapidary work.
Geological facts
Chert includes well-known varieties such as flint and jasper. It has been utilized by humans for toolmaking since the Paleolithic era.
Field identification & locations
Identify by its extreme hardness, vitreous to waxy luster, and smooth conchoidal fracture. Commonly found within limestone and chalk formations 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
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