sedimentary

Chalcedony-rich jasper (orbicular/pisolithic jasper)

Microcrystalline quartz (SiO₂), commonly with iron-oxide pigments and possible quartz pseudospheres

AI-generated identification · may be incorrect

Brown-red, opaque, earthy to slightly waxy luster, composed of microscopic quartz; hardness about 6.5–7 Mohs, no cleavage, specific gravity ~2.55–2.65. The rounded pale spots suggest orbicular or pisolitic texture.

Identified August 31, 2026More sedimentary →

Explore Chalcedony-rich jasper (orbicular/pisolithic jasper) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Silica-rich groundwater replaced or cemented volcanic ash, breccia, or sediment, while iron oxides produced the brown-red coloration; age varies widely by deposit. Exact locality cannot be determined from the photograph.

Uses & applications

Used as a lapidary stone for cabochons, beads, carvings, and polished specimens; occasionally decorative aggregate. Common material generally has modest commercial value.

Geological facts

Jasper is an opaque variety of chalcedony, and its patterns often reflect fluid alteration rather than true sedimentary bedding. Orbicular varieties are prized for their concentric or rounded internal markings.

Field identification & locations

Commonly found as dense, heavy, opaque brown or red pebbles in volcanic terrains and alluvial gravels; a glassy fracture, quartz hardness, and inability to scratch it with a steel knife support identification. Acid produces no reaction.