mineral
Polished jasper (likely brecciated or red jasper)
Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide pigments and possible breccia fragments
AI-generated identification · may be incorrectOpaque reddish-brown, fine-grained, and weakly to moderately glossy where polished; hardness about 6.5–7 Mohs, no visible cleavage, conchoidal fracture, and specific gravity around 2.5–2.7. Pale angular patches may be quartz/chalcedony or weathered matrix.
Identified More mineral →
Explore Polished jasper (likely brecciated or red jasper) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Opaque reddish-brown, fine-grained, and weakly to moderately glossy where polished; hardness about 6.5–7 Mohs, no visible cleavage, conchoidal fracture, and specific gravity around 2.5–2.7. Pale angular patches may be quartz/chalcedony or weathered matrix.
Formation & geological history
Forms when silica-rich groundwater fills cavities or replaces volcanic and sedimentary material, with iron oxides producing the red-brown color; commonly Cenozoic to older, depending on the deposit. The specimen appears cut and polished from a natural nodule or slab.
Uses & applications
Used for cabochons, beads, carvings, ornaments, and lapidary pieces; historically used for tools and decorative stone. It has modest value unless pattern, polish, or provenance is exceptional.
Geological facts
Jasper is an opaque variety of chalcedony rather than a single mineral species. Red coloration generally reflects hematite or limonite inclusions.
Field identification & locations
Check for uniform fine texture, opaque red coloration, glassy conchoidal edges, and hardness sufficient to scratch glass; it should not fizz in dilute acid. Common sources include India, Madagascar, Brazil, Australia, Mexico, and the western United States.
