mineral

Polished brecciated jasper or agate

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions and brecciation

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; mottled red, brown, gray, and translucent white areas; waxy to vitreous luster; cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded surface indicates tumbling or polishing.

Identified September 17, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich groundwater filled fractures or replaced rock, with iron oxides producing the red-brown colors; later weathering released the nodule. Precise age and locality cannot be determined from the photograph.

Uses & applications

Used as an ornamental stone, cabochon, bead, and lapidary material; attractive pieces have modest jewelry and collecting value.

Geological facts

The specimen appears brecciated, meaning angular fragments were cemented by later silica. Strong translucency and quartz-like hardness help distinguish it from ordinary opaque jasper.

Field identification & locations

Test carefully on an inconspicuous edge: it should scratch window glass but not be scratched by a steel knife. Common sources include Oregon, Idaho, Utah, Brazil, Madagascar, and Australia; exact identification requires locality or testing.