sedimentary
Chert / Flint (Arrowhead)
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, earthy to waxy luster, conchoidal fracture, and typically gray, brown, or greenish in color.
Identified More sedimentary →
Explore Chert / Flint (Arrowhead) 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, earthy to waxy luster, conchoidal fracture, and typically gray, brown, or greenish in color.
Formation & geological history
Formed through the chemical replacement of limestone or chalk by silica-rich groundwaters in marine environments over millions of years.
Uses & applications
Historically used for making stone tools and projectile points; currently collected as an artifact or geological specimen.
Geological facts
Prehistoric humans heavily favored chert and flint for knapping stone tools due to its predictable conchoidal fracture pattern.
Field identification & locations
Identify by its distinct conchoidal fracture edges and hardness that scratches glass; frequently found in limestone formations and river gravels 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