mineral

Tumbled quartz-rich stone, likely brown agate or jasper

Microcrystalline silica (chalcedony/quartz, SiO₂), possibly iron-stained agate or jasper

AI-generated identification · may be incorrect

Rounded and polished, translucent brown-tan body with subtle cloudy banding; vitreous to waxy luster and no visible cleavage. Hardness about 6.5–7 Mohs; specific gravity approximately 2.6.

Identified August 15, 2026More mineral →

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Physical properties

Rounded and polished, translucent brown-tan body with subtle cloudy banding; vitreous to waxy luster and no visible cleavage. Hardness about 6.5–7 Mohs; specific gravity approximately 2.6.

Formation & geological history

Formed when silica-rich groundwater filled cavities or fractures in volcanic rock, later acquiring iron-oxide coloration; commonly Cenozoic to older, depending on locality. Tumbled and polished by human processing.

Uses & applications

Used as a decorative stone, worry stone, cabochon, or small collectible; quartz varieties are also used for abrasives and ornamental objects.

Geological facts

The image does not show enough diagnostic detail for a precise variety; it could also be a polished brown quartzite or iron-stained chalcedony.

Field identification & locations

Quartz-rich stones resist scratching by a steel knife and usually scratch glass; agate may show curved bands, while jasper is typically opaque and uniform. Common sources include Brazil, Uruguay, Mexico, Madagascar, and the western United States.