metamorphic

Tumbled brown jasper

Jasper, microcrystalline quartz (SiO₂) with iron-oxide impurities

AI-generated identification · may be incorrect

Opaque reddish-brown to chocolate-brown, polished, with dull-to-glassy luster; typically hardness 6.5–7 Mohs, no visible cleavage, cryptocrystalline quartz structure, and specific gravity about 2.6.

Identified September 2, 2026More metamorphic →

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Physical properties

Formation & geological history

Jasper forms when silica-rich fluids cement or replace fine sediments and volcanic material, with iron oxides producing the brown-red color. Its age varies widely, from Precambrian to younger volcanic or sedimentary settings.

Uses & applications

Used for tumbled stones, cabochons, carvings, ornaments, and inexpensive jewelry; occasionally used decoratively as facing or small architectural stone.

Geological facts

Jasper is technically an opaque variety of chalcedony or microcrystalline quartz. Brown coloration commonly reflects hematite, goethite, or other iron minerals.

Field identification & locations

Identify it by its opaque earthy color, fine texture, strong polish, and inability to scratch with a steel knife; quartz or glass can scratch it. Common sources include India, Brazil, Madagascar, Australia, and the western United States.