sedimentary
Chert (Flint)
Chert (̑SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs), Color: Gray, blue-gray, or tan, Luster: Waxy to vitreous, Structure: Microcrystalline/Cryptocrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
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: 7 (Mohs), Color: Gray, blue-gray, or tan, Luster: Waxy to vitreous, Structure: Microcrystalline/Cryptocrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7
Formation & geological history
Formed via the accumulation of silica-rich organic remains (like radiolarians or diatoms) or by chemical precipitation from silica-rich fluids within sedimentary rock layers like limestone or chalk.
Uses & applications
Historically used for stone tools and weapons. Modernly used in construction aggregate, road surfacing, jewelry (as jasper or agate varieties), and as a fire-starter in survival gear.
Geological facts
Flint is a variety of chert that was essential to prehistoric humans for creating sharp-edged tools. When struck against steel, it produces sparks, which led to its use in flintlock firearms.
Field identification & locations
Identify by its characteristic waxy appearance and shell-like (conchoidal) fracture pattern when broken. It is commonly found in nodular or layered form within limestone outcrops and on riverbanks.
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