sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on Mohs scale, waxy to vitreous luster, conchoidal fracture, and colors ranging from white to dark brown or black.
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 Mohs scale, waxy to vitreous luster, conchoidal fracture, and colors ranging from white to dark brown or black.
Formation & geological history
Formed via the chemical precipitation of silica from aqueous solutions or the accumulation of siliceous skeletal remains of marine organisms over millions of years.
Uses & applications
Historically used by early humans for stone tools and projectile points due to its sharp conchoidal fracture, and occasionally as a decorative or abrasive material.
Geological facts
Chert forms nodules or layers within sedimentary rock formations, most notably in limestone or chalk deposits. Varieties include flint, jasper, and agate.
Field identification & locations
Identified by its high hardness (scratches glass), waxy luster, and sharp conchoidal edges. Commonly found worldwide in limestone and marine sedimentary deposits.
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