mineral

Tumbled brown stone, likely jasper or chert

Microcrystalline quartz (SiO₂), probably iron-stained jasper/chert

AI-generated identification · may be incorrect

Opaque brown-gray, smooth and wet-polished with a dull to waxy luster; quartz hardness is about 6.5–7 Mohs, with no visible cleavage and conchoidal fracture. Exact identification requires testing because the image cannot distinguish jasper from chert or other dark silica stones.

Identified August 12, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids cement or replace sediment, often with iron oxides producing the brown color; jasper commonly develops in volcanic or sedimentary settings. Ages may range from Precambrian to recent, depending on the deposit.

Uses & applications

Used as a low-cost ornamental and lapidary stone for tumbling, cabochons, carvings, and decorative objects; generally not used structurally.

Geological facts

Jasper is an opaque variety of chalcedony, while chert is a broader term for dense microcrystalline quartz. Iron staining commonly creates brown, red, yellow, or orange tones.

Field identification & locations

Common in gravel beds and silica-rich formations worldwide; scratch testing with steel or glass, checking for conchoidal fracture, and observing translucency at thin edges can help distinguish it. Value is typically $1–$10 as a small tumbled stone, or $10–$40 for attractive patterned material.