sedimentary
Chert (Flint)
Silicon Dioxide (SiO2)
Hardness of 7 on Mohs scale, microcrystalline quartz, smooth waxy to dull luster, sharp conchoidal fracture, opaque to translucent, tan/brownish color.
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 Mohs scale, microcrystalline quartz, smooth waxy to dull luster, sharp conchoidal fracture, opaque to translucent, tan/brownish color.
Formation & geological history
Formed through biochemical sedimentary processes or chemical precipitation from silica-rich fluids replacing limestone or chalk beds.
Uses & applications
Historically used for making stone tools and starting fires due to sparks generated against steel. Used today in flint knapping, gravel, and decorative stone collecting.
Geological facts
Chert fracture patterns produce razor-sharp edges, making it a critical toolmaking resource for prehistoric humans worldwide.
Field identification & locations
Identify in the field by its distinct waxy texture, lack of cleavage, extreme hardness (scratches glass easily), and curved conchoidal fracture edges. Found abundantly in sedimentary formations and stream beds.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Shale
Shale (clastic sedimentary rock)
sedimentary
Brown Sandstone (River Rock)
Arenite
sedimentary
Shale
Argillaceous sedimentary rock
sedimentary