mineral

Tumbled brown chalcedony or jasper

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper

AI-generated identification · may be incorrect

Opaque to slightly translucent brown, smooth tumbled surface, vitreous-to-waxy luster, cryptocrystalline structure, no visible cleavage; Mohs hardness 6.5–7 and specific gravity about 2.6. The image alone cannot distinguish jasper from brown chalcedony confidently.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids fill cavities or fractures, with iron oxides producing the brown color; deposits range from Precambrian to recent. Tumbled pieces are mechanically rounded and polished from rough material.

Uses & applications

Used as inexpensive lapidary material for cabochons, beads, carvings, and decorative objects; commonly sold as a small pocket or display stone.

Geological facts

Jasper is the opaque variety, while chalcedony is typically translucent; many commercial pieces are trade-name varieties rather than formally distinct minerals.

Field identification & locations

Look for quartz-like hardness, resistance to scratching by steel, and a white streak; it should not fizz in dilute hydrochloric acid. Common sources include Brazil, India, Madagascar, Uruguay, and the western United States.