sedimentary
Jasper / Chert (Tumbled)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 (Mohs scale), Color: Opaque yellowish-brown to orange-brown, Luster: Waxy to dull (when dry), Vitreous when wet or polished, Crystal structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture).
- Hardness
- 6
Identified More sedimentary →
Explore Jasper / Chert (Tumbled) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs scale), Color: Opaque yellowish-brown to orange-brown, Luster: Waxy to dull (when dry), Vitreous when wet or polished, Crystal structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture).
Formation & geological history
Forms from the deposition and consolidation of silica-rich fluids in sedimentary environments or as nodules in limestone/chalk. The color is typically due to iron oxide impurities (limonite or goethite).
Uses & applications
Commonly used in rock tumbling, jewelry making (cabochons, beads), and as decorative stones.
Geological facts
Jasper is an opaque variety of chalcedony. Yellow and brown jaspers are very common worldwide and have been used historically for tools and ornamentation.
Field identification & locations
Can be identified by its opacity, hardness (scratches glass), and conchoidal fracture. Often found in riverbeds and gravel deposits where they have been naturally rounded by water action.
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
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary