mineral

Tumbled jasper (likely brecciated or mahogany jasper)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide inclusions

AI-generated identification · may be incorrect

Opaque, dark brown to reddish-brown, with a vitreous-to-waxy luster and rounded tumbled surfaces. Mohs hardness 6.5–7; no visible cleavage; cryptocrystalline quartz structure; specific gravity about 2.55–2.70.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater replaces or fills cavities in volcanic rocks, with iron oxides producing the brown-red coloration and possible brecciation. Most jasper is Cenozoic to older, depending on locality.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and ornamental objects; generally inexpensive as a small tumbled specimen.

Geological facts

Jasper is an opaque variety of chalcedony rather than a single mineral species. The pale angular patches and reddish seam may indicate brecciated jasper or a mixed jasper-chalcedony piece.

Field identification & locations

Identify by its opacity, fine texture, waxy/glassy luster, lack of cleavage, and resistance to scratching; it should not be scratched by a steel knife easily. Common sources include India, Madagascar, Brazil, Australia, Mexico, and the western United States.