sedimentary

Tumbled orbicular jasper

Orbicular jasper; microcrystalline quartz (SiO₂) with iron oxides and feldspathic/chalcedony inclusions

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, opaque, brown to reddish-gray with cream orbicules, and a vitreous to waxy luster; cryptocrystalline, with no visible cleavage. The polished surface is rounded and glossy.

Identified August 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when silica-rich fluids cement volcanic or sedimentary material, producing concentric orbicular patterns around mineral nuclei; individual deposits vary widely in age, commonly Paleozoic to Cenozoic. This specimen has been cut and tumbled.

Uses & applications

Used for cabochons, beads, carvings, worry stones, and decorative objects; it has little industrial use. Attractive patterning gives it modest collector value.

Geological facts

Orbicular jasper is a trade name rather than one single mineral species; similar-looking materials include ocean jasper, leopard jasper, and rhyolite-based orbicular stones.

Field identification & locations

Identify it by its opaque body, rounded cream-to-white orbs, reddish-brown matrix, and lack of translucency; common sources include Madagascar, Mexico, Australia, and the western United States. A hand lens may reveal quartz-like microtexture.