sedimentary
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs); Color: Tan, beige, brown; Luster: Waxy to dull; Crystal structure: Microcrystalline/cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
- Hardness
- 7 (Mohs)
- Color
- Tan, beige, brown
- Luster
- Waxy to dull
Identified More sedimentary →
Explore Chert (Jasper/Flint variant) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs); Color: Tan, beige, brown; Luster: Waxy to dull; Crystal structure: Microcrystalline/cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Formed through the accumulation of silica-rich organic remains (like diatoms or radiolarians) or chemical precipitation in marine environments; often occurs as nodules in limestone or chalk beds.
Uses & applications
Historically used for stone tools (arrowheads/knives) due to its sharp conchoidal edges; currently used in construction aggregate and as a collector's specimen.
Geological facts
Chert was one of the most important minerals for early humans because its predictable fracturing allowed for the creation of precise, razor-sharp tools and weapons.
Field identification & locations
Identify by its extreme hardness (scratches glass), waxy texture, and shell-like (conchoidal) fracture pattern. Commonly found in riverbeds or eroding out of limestone cliffs.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary