sedimentary
Chert (Jasper)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 Mohs; Color: reddish-brown, tan, and gray waxy luster; Conchoidal fracture; Opaque to translucent; Trigonal crystal system (microscopic).
- Hardness
- 6
- Color
- reddish-brown, tan, and gray waxy luster
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: reddish-brown, tan, and gray waxy luster; Conchoidal fracture; Opaque to translucent; Trigonal crystal system (microscopic).
Formation & geological history
Formed through the accumulation of silica-rich organic remains or chemical precipitation in sedimentary environments. The reddish hues suggest iron oxide mineralization.
Uses & applications
Historically used for stone tools and arrowheads; currently used in jewelry (as jasper), landscaping, and as an industrial abrasive.
Geological facts
Chert is so hard it can strike sparks from steel. Varieties rich in iron oxide are specifically known as jasper, often used as semi-precious gemstones.
Field identification & locations
Look for a smooth, waxy surface and conchoidal (shell-like) fractures. Common in riverbeds and limestone outcrops. Often found as rounded nodules or pebbles.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary