sedimentary

Tumbled brown jasper (likely iron-rich chert)

Microcrystalline quartz, SiO₂, with iron-oxide impurities

AI-generated identification · may be incorrect

Opaque brown to reddish-brown, earthy to waxy luster, conchoidal fracture, no visible cleavage; Mohs hardness about 6.5–7 and specific gravity roughly 2.6. The surface appears naturally or mechanically smoothed, with a darker weathered rind.

Identified August 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Jasper forms when silica-rich fluids replace or cement sediment, commonly producing iron-stained microcrystalline quartz; deposits range from Precambrian to recent. The specimen was likely broken and tumbled or polished after collection.

Uses & applications

Used for cabochons, beads, carvings, lapidary pieces, and decorative stone; occasionally as a minor aggregate. It is generally a common collector material rather than a high-value gemstone.

Geological facts

Jasper is a variety of chert distinguished mainly by its opacity and abundant impurities. Brown coloration typically comes from hematite, goethite, or other iron oxides.

Field identification & locations

Identify it by testing for glass-scratching hardness, observing conchoidal fracture, and checking that it is opaque rather than translucent like chalcedony. Common sources include India, Madagascar, Brazil, Australia, and the western United States.