sedimentary
Flint
Cryptocrystalline quartz (SiO2)
Hardness of 7 on the Mohs scale, colors range from grey, white, brown to black, waxy to vitreous luster, conchoidal fracture with no cleavage, specific gravity around 2.60 to 2.65.
Identified More sedimentary →
Explore 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, colors range from grey, white, brown to black, waxy to vitreous luster, conchoidal fracture with no cleavage, specific gravity around 2.60 to 2.65.
Formation & geological history
Formed through the chemical replacement of calcium carbonate in limestone or chalk by silica-rich solutions in marine environments over millions of years.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire; currently used in abrasives, decorative gravel, and construction.
Geological facts
Flint is extremely durable and has been utilized by humans for hundreds of thousands of years due to its sharp conchoidal fracture when struck.
Field identification & locations
Found commonly as nodules or masses embedded in chalk or limestone deposits worldwide. Identified easily by its conchoidal fracture and high hardness.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary