sedimentary
Flint (chert)
Microcrystalline quartz (SiO₂), a variety of chert
AI-generated identification · may be incorrectDense, fine-grained stone with a dull-to-waxy luster, gray-brown coloration, and conchoidal fracture with sharp edges; hardness about 7 Mohs. The image shows a broken flake surface and weathered brown cortex.
Identified More sedimentary →
Explore Flint (chert) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dense, fine-grained stone with a dull-to-waxy luster, gray-brown coloration, and conchoidal fracture with sharp edges; hardness about 7 Mohs. The image shows a broken flake surface and weathered brown cortex.
Formation & geological history
Forms as silica-rich nodules or layers in sedimentary rocks, commonly limestone or chalk, through diagenetic replacement. Its age depends on the host formation; flint deposits range from Paleozoic to Cenozoic.
Uses & applications
Historically used for tools and fire-starting; today collected and sometimes used in decorative stonework.
Geological facts
Flint fractures into sharp flakes, making it an important material for prehistoric blades and scrapers.
Field identification & locations
Look for a smooth, curved fracture face, sharp edges, and a contrasting weathered outer rind. Common in chalk and limestone regions, including parts of Europe and North America.
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
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary