mineral
Tumbled jasper (likely brown jasper)
Microcrystalline quartz/chalcedony (SiO₂), colored mainly by iron oxides
AI-generated identification · may be incorrectOpaque reddish-brown to chocolate-brown, smooth waterworn/tumbled surface, dull to waxy luster, and no visible cleavage; hardness about 6.5–7 Mohs, specific gravity roughly 2.5–2.7. Exact identification is limited by the photograph.
Identified More mineral →
Explore Tumbled jasper (likely brown jasper) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Opaque reddish-brown to chocolate-brown, smooth waterworn/tumbled surface, dull to waxy luster, and no visible cleavage; hardness about 6.5–7 Mohs, specific gravity roughly 2.5–2.7. Exact identification is limited by the photograph.
Formation & geological history
Forms when silica-rich fluids fill cavities or replace rock, with iron producing the brown-red coloration; deposits range from Precambrian to much younger volcanic and sedimentary settings. This specimen appears human-tumbled or naturally rounded.
Uses & applications
Used for cabochons, beads, carvings, lapidary décor, and inexpensive collectibles; rarely used as aggregate or ornamental stone.
Geological facts
Jasper is an opaque variety of chalcedony, unlike transparent quartz varieties such as amethyst. Patterns and colors vary widely with the incorporated iron minerals and host rock.
Field identification & locations
Identify by its opaque earthy color, very fine texture, glass-scratching hardness, and lack of fizz in dilute acid; common sources include India, Madagascar, Brazil, Australia, and the western United States. A scratch test should be performed only if damage is acceptable.
