sedimentary
Chert / Flint
Microcrystalline Quartz (SiO2)
Hardness of 7 on the Mohs scale, earthy to waxy luster, concoidal fracture, colors range from white, grey, brown to black, specific gravity around 2.60.
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 of 7 on the Mohs scale, earthy to waxy luster, concoidal fracture, colors range from white, grey, brown to black, specific gravity around 2.60.
Formation & geological history
Formed via the replacement of calcium carbonate by silica in marine environments or the accumulation of siliceous oozes from microscopic organisms, generally dating from the Mesozoic and Cenozoic eras.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire; currently used in aggregate, abrasive industries, and decorative landscaping.
Geological facts
Chert and flint are chemically identical; flint is traditionally the darker variety found in chalk, while chert is found in limestone. It was one of the most critical materials for early human technological development due to its sharp edges when fractured.
Field identification & locations
Can be identified in the field by its distinct conchoidal fracture and high hardness (scratches glass). Commonly found globally in limestone and chalk formations.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
sedimentary