sedimentary
Chert (Jasper)
Silicon dioxide (SiO2) with impurities
AI-generated identification · may be incorrectHardness: 6.5-7 (Mohs); Color: Mottled red, yellow, and tan; Luster: Waxy to dull; Crystal structure: Microcrystalline quartz; Cleavage: None (conchoidal fracture).
- Hardness
- 6
- Color
- Mottled red, yellow, and tan
- Luster
- Waxy to dull
Identified More sedimentary →
Explore Chert (Jasper) 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: Mottled red, yellow, and tan; Luster: Waxy to dull; Crystal structure: Microcrystalline quartz; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed through the accumulation of silica-rich fluids within sedimentary environments or replacing other minerals. This water-worn specimen likely originated in a riverbed or glacial deposit.
Uses & applications
Primarily used for lapidary work, jewelry (beads/cabochons), and as landscaping stone. Historically used for making sharp tools and arrowheads.
Geological facts
This specimen is a river-rounded pebble showing classic jasper coloration caused by varying levels of iron oxide (hematite for red, goethite for yellow).
Field identification & locations
Identify in the field by its smooth, waxy texture and inability to be scratched by a steel knife. It often features colorful mottling or banding. Commonly found in gravel pits and along stream banks.
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