sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to dark gray or brown.
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, conchoidal fracture, and colors ranging from white to dark gray or brown.
Formation & geological history
Formed through the chemical precipitation of silica from seawater or the replacement of limestone during the Cretaceous and other periods.
Uses & applications
Historically used for stone tools and weapons due to its sharp edges when fractured; currently used in abrasives and decorative landscaping.
Geological facts
Chert forms in marine environments when siliceous oozes from microscopic organisms compact and recrystallize over millions of years.
Field identification & locations
Identified easily by its conchoidal fracture and high hardness that scratches glass; commonly found within limestone and chalk formations 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