mineral
Tumbled brown jasper or chalcedony
Microcrystalline quartz (SiO₂), likely iron-stained jasper/chalcedony
AI-generated identification · may be incorrectHardness 6.5–7 Mohs; opaque to slightly translucent, brown to olive-brown with cloudy yellow patches and a smooth glassy/waxy luster. It has a cryptocrystalline quartz structure and no visible cleavage; specific gravity is about 2.6.
Identified More mineral →
Explore Tumbled brown jasper or chalcedony in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness 6.5–7 Mohs; opaque to slightly translucent, brown to olive-brown with cloudy yellow patches and a smooth glassy/waxy luster. It has a cryptocrystalline quartz structure and no visible cleavage; specific gravity is about 2.6.
Formation & geological history
Forms when silica-rich fluids fill cavities or replace volcanic sediment, with iron oxides producing the brown coloration. The specimen is tumbled and polished, so its precise geological age and source cannot be determined from the image.
Uses & applications
Used as a decorative stone, worry stone, cabochon, beads, and small carvings; polished jasper is primarily valued for appearance rather than rarity.
Geological facts
Jasper is an opaque variety of chalcedony, while chalcedony is translucent to semi-translucent microcrystalline quartz. Brown coloration commonly reflects hematite, goethite, or other iron-bearing impurities.
Field identification & locations
Identify it by its very smooth polish, waxy/glassy surface, quartz-like hardness, and opaque earthy pattern; it should resist scratching by a steel knife. Common sources include Brazil, India, Madagascar, Australia, and the western United States.
