sedimentary
Chert (Iron-stained)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs scale), Color: tan, white, and reddish-brown due to hematite staining, Luster: waxy to dull, Structure: microcrystalline quartz, Cleavage: none (conchoidal fracture)
Identified More sedimentary →
Explore Chert (Iron-stained) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs scale), Color: tan, white, and reddish-brown due to hematite staining, Luster: waxy to dull, Structure: microcrystalline quartz, Cleavage: none (conchoidal fracture)
Formation & geological history
Formed as a chemical precipitate from silica-rich fluids or the accumulation of siliceous remains of organisms like diatoms and radiolaria. Found in sedimentary basins.
Uses & applications
Used historically for stone tools due to sharp edges; currently used for landscaping, road base, and as a decorative stone in gardening.
Geological facts
Chert is extremely durable and chemically resistant. It often occurs as nodules or beds within limestone or chalk formations. Iron-stained varieties are often colloquially called jasper if opaque and colorful.
Field identification & locations
Identify by its extreme hardness (cannot be scratched by a steel knife) and its smooth, shell-like (conchoidal) fracture pattern. Commonly found in river beds or landscaping mulch.
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