sedimentary
Chert (or Jasper)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically brown, reddish-brown, or yellow-brown color, waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture with no true cleavage, specific gravity of roughly 2.60 to 2.65.
Identified More sedimentary →
Explore Chert (or Jasper) 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, typically brown, reddish-brown, or yellow-brown color, waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture with no true cleavage, specific gravity of roughly 2.60 to 2.65.
Formation & geological history
Formed in marine environments through the chemical precipitation of silica from seawater or the replacement of limestone or chalk by silica-rich solutions during diagenesis.
Uses & applications
Historically used by early humans for making stone tools, arrowheads, and blades due to its conchoidal fracture. Today used occasionally in decorative lapidary work and landscaping.
Geological facts
Chert and flint are essentially the same material; the term chert is generally applied to varieties found in limestone, while flint is often reserved for dark or black varieties found in chalk.
Field identification & locations
Easily identified in the field by its hardness (scratches glass easily), waxy luster, and sharp conchoidal fracture edges. Widely found worldwide in sedimentary rock formations.
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