sedimentary
Flint
Microcrystalline quartz (SiO2)
Hardness of 7 on the Mohs scale, color ranges from grey, white, to brown and black, vitreous to dull luster, cryptocrystalline structure, conchoidal fracture with no cleavage, specific gravity of 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, color ranges from grey, white, to brown and black, vitreous to dull luster, cryptocrystalline structure, conchoidal fracture with no cleavage, specific gravity of 2.60 to 2.65.
Formation & geological history
Formed in chalk or marly limestone by the replacement of calcium carbonate with silica-rich solutions during the Cretaceous period.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire. Modern uses include decorative landscaping, aggregates, and historically in flintlock firearms.
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
Commonly found embedded in chalk cliffs or along beaches where chalk erodes. Easily identified by its weathered white outer cortex and dark interior with sharp edges.
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