sedimentary
Chert (or Petrifed Wood / Banded Flint)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness 7 on Mohs scale, waxy to dull luster, conchoidal fracture, sharp edges when broken, microcrystalline quartz structure.
Identified More sedimentary →
Explore Chert (or Petrifed Wood / Banded Flint) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness 7 on Mohs scale, waxy to dull luster, conchoidal fracture, sharp edges when broken, microcrystalline quartz structure.
Formation & geological history
Formed through the accumulation of silica-rich biogenic sediments or chemical precipitation in marine or continental groundwater environments, often replacing organic structures or filling cavities.
Uses & applications
Used historically for stone tools, flintknapping, decorative landscaping rocks, and lapidary art.
Geological facts
Chert has been utilized since prehistoric times due to its predictable conchoidal fracture, allowing humans to fashion extremely sharp arrowheads, scrapers, and blades.
Field identification & locations
Look for smooth, waxy surfaces with sharp conchoidal fractures and a hardness capable of scratching steel. Commonly found in limestone formations, sedimentary beds, and gravel deposits.
More like this
Other sedimentary specimens
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
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary