sedimentary
Chert
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, microcrystalline quartz structure, conchoidal fracture, and colors ranging from white to gray and 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 the Mohs scale, waxy luster, microcrystalline quartz structure, conchoidal fracture, and colors ranging from white to gray and black.
Formation & geological history
Formed through the chemical precipitation of silica from seawater or the accumulation of siliceous microfossil remains over millions of years.
Uses & applications
Historically used by early humans for stone tools and arrowheads due to its sharp conchoidal fracture; occasionally used for decorative landscaping.
Geological facts
Chert often occurs as nodules or concretions inside limestone and chalk formations and includes varieties like flint and jasper.
Field identification & locations
Identified in the field by its extreme hardness, waxy sheen, and sharp, shell-like fracture edges. Commonly found globally within sedimentary carbonate rock layers.
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