sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically brown, gray, or white in color.
Identified More sedimentary →
Explore Chert in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically brown, gray, or white in color.
Formation & geological history
Formed through the chemical precipitation of silica from seawater or the replacement of limestone during the Cretaceous period.
Uses & applications
Historically used by early humans for making stone tools and arrowheads due to its sharp edges when fractured.
Geological facts
Chert breaks with a distinct conchoidal fracture, producing extremely sharp edges that made it vital for ancient weaponry and cutting tools.
Field identification & locations
Identify in the field by its dense structure, waxy luster, and conchoidal fracture; commonly found embedded in limestone formations worldwide.
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