sedimentary
Chert / Flint
Microcrystalline Quartz (SiO2)
Hardness of 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, colors range from white, grey, brown to yellow and black, cryptocrystalline structure, 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, waxy to vitreous luster, conchoidal fracture, colors range from white, grey, brown to yellow and black, cryptocrystalline structure, specific gravity around 2.60.
Formation & geological history
Formed through the chemical or biochemical precipitation of silica from aqueous solutions, often replacing carbonate rocks (limestone or chalk) during diagenesis. Can form in marine environments over millions of years.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire due to its sharp conchoidal fracture. Today used in abrasives, road aggregates, and decorative landscaping.
Geological facts
Known as flint when dark-colored and found in chalk deposits. It was one of the most critical materials for early human survival and tool-making.
Field identification & locations
Easily identified by its extreme hardness, smooth waxy surface, and sharp conchoidal edges. Commonly found in limestone and chalk formations worldwide.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
sedimentary