sedimentary
Chert Nodule
Microcrystalline Quartz
AI-generated identification · may be incorrectHardness: 6.5-7 (Mohs), Color: Cream, tan, gray, brown, Luster: Waxy to dull, Fracture: Conchoidal
- Hardness
- 6
- Luster
- Waxy to dull, Fracture: Conchoidal
Identified More sedimentary →
Explore Chert Nodule in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs), Color: Cream, tan, gray, brown, Luster: Waxy to dull, Fracture: Conchoidal
Formation & geological history
Formed by the chemical precipitation of silica in sedimentary environments, often within limestone or chalk deposits. Commonly found as nodules or concretions.
Uses & applications
Historically used for making stone tools (flintknapping) due to its conchoidal fracture. Sometimes used as a low-grade aggregate or in landscaping.
Geological facts
Chert and flint are closely related, with flint specifically referring to dark chert found in chalk. The sharp edges created when broken made it a crucial material for early human tools and weapons.
Field identification & locations
Identify by its hardness (scratches glass), waxy luster, and conchoidal fracture. Often found as rounded or irregular nodules eroding out of limestone.
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