sedimentary
Flint
SiO2 (Cryptocrystalline Quartz)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically dark brown or gray, waxy to vitreous luster, with 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 dark brown or gray, waxy to vitreous luster, with conchoidal fracture.
Formation & geological history
Formed through the chemical replacement of limestone or chalk by silica-rich solutions during the Cretaceous period.
Uses & applications
Historically used for making stone tools and striking fire; currently used in landscaping and abrasives.
Geological facts
Flint produces sparks when struck against steel due to its high hardness and microcrystalline structure.
Field identification & locations
Identified by its sharp conchoidal edges, waxy luster, and occurrence as nodules within chalk formations.
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