sedimentary
Chert / Flint
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy or vitreous luster, conchoidal fracture, and colors ranging from gray to brown.
Identified More sedimentary →
Explore Chert / Flint 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 or vitreous luster, conchoidal fracture, and colors ranging from gray to brown.
Formation & geological history
Formed through the chemical precipitation of silica from aqueous solutions or the replacement of limestone by silica-rich fluids over millions of years.
Uses & applications
Historically used for making stone tools and weapons due to its sharp edges; modern uses include abrasives and aggregate.
Geological facts
Ancient humans prized chert and flint for knapping into arrowheads and spear points because of its predictable fracture patterns.
Field identification & locations
Identify by its distinct conchoidal fracture, sharp edges, and ability to scratch glass easily. Commonly found within chalk or 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