sedimentary
Chert / Flint
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy to dull luster, conchoidal fracture, and typically colored gray, brown, white, or black.
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 the Mohs scale, waxy to dull luster, conchoidal fracture, and typically colored gray, brown, white, or black.
Formation & geological history
Formed through the chemical precipitation of silica-rich fluids or accumulation of siliceous skeletal remains in marine environments over millions of years.
Uses & applications
Historically used for making stone tools, arrowheads, and spark strikers, and currently utilized in industrial abrasives and decorative landscaping.
Geological facts
Chert and flint are chemically identical, with 'flint' typically reserved for darker varieties found in chalk deposits. It was a vital survival material for ancient human civilizations due to its predictable fracturing.
Field identification & locations
Identify in the field by its distinct conchoidal fracture and extreme hardness that easily scratches glass. Commonly found within limestone or 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