sedimentary
Flint
Cryptocrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically brown or gray in color, waxy to vitreous luster, and exhibits conchoidal fracture.
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, typically brown or gray in color, waxy to vitreous luster, and exhibits conchoidal fracture.
Formation & geological history
Formed by the replacement of calcium carbonate by silica in chalk or limestone formations during the Cretaceous period.
Uses & applications
Historically used for making stone tools and fire-starting; currently used in abrasives, ceramics, and specialty landscaping.
Geological facts
Prehistoric humans heavily favored flint for knapping sharp blades and arrowheads due to its predictable conchoidal fracture.
Field identification & locations
Identify in the field by its distinctive conchoidal fracture, waxy luster, and occurrence as nodules within chalk or limestone beds.
More like this
Other sedimentary specimens
Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion
Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image
fossil
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary