sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectMohs hardness of 7, vitreous to dull luster, conchoidal fracture, and colors ranging from white to brown and gray.
Identified More sedimentary →
Explore Chert in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Mohs hardness of 7, vitreous to dull luster, conchoidal fracture, and colors ranging from white to brown and gray.
Formation & geological history
Formed via the accumulation of siliceous microfossil remains or the chemical replacement of limestone during sedimentary diagenesis.
Uses & applications
Historically used for making stone tools and fire-starters; modern use includes abrasives and decorative landscaping.
Geological facts
Ancient humans prized chert and flint for sharp edges, making it critical for prehistoric survival and weapon manufacturing.
Field identification & locations
Identify by extreme hardness, conchoidal fracture, and inability to be scratched by steel; found globally in limestone formations.
More like this
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