sedimentary
Flint / Chert
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, opaque to translucent, colors commonly grey, dark grey, white, or yellowish due to impurities.
Identified More sedimentary →
Explore Flint / 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 to vitreous luster, conchoidal fracture, opaque to translucent, colors commonly grey, dark grey, white, or yellowish due to impurities.
Formation & geological history
Formed through the replacement of calcium carbonate by silica-rich solutions in marine environments (such as chalk or limestone formations) over millions of years.
Uses & applications
Historically used for making stone tools, weapons, and fire-starting. Today used in decorative landscaping, abrasives, and by historical reenactors.
Geological facts
Flint was one of the earliest materials manipulated by early humans to create sharp cutting edges and arrowheads due to its predictable conchoidal fracture.
Field identification & locations
Can be identified in the field by its distinctive smooth, water-worn exterior (if a pebble), conchoidal fracture showing sharp edges when broken, and high hardness capable of scratching glass.
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