sedimentary
Jasper / Chert (river tumbled)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness of 6.5-7 on Mohs scale. Opaque brown/tan color with some lighter and darker mottling. Waxy luster when wet or polished. Conchoidal fracture. Cryptocrystalline structure.
Identified More sedimentary →
Explore Jasper / Chert (river tumbled) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 6.5-7 on Mohs scale. Opaque brown/tan color with some lighter and darker mottling. Waxy luster when wet or polished. Conchoidal fracture. Cryptocrystalline structure.
Formation & geological history
Formed from silica-rich fluids precipitating in sedimentary environments. This specimen has been rounded by natural water action in a river or beach environment.
Uses & applications
Commonly used for lapidary work, tumbling, and decorative stones. Historically used for making stone tools.
Geological facts
Jasper is a variety of chalcedony that gets its opaque color from mineral impurities, often iron oxides.
Field identification & locations
Identified by its hardness (scratches glass), opaque nature, conchoidal fracture, and waxy feel. Very common in riverbeds and gravel deposits worldwide.
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