sedimentary

Orbicular jasper (ocean jasper-like jasper)

Microcrystalline quartz (SiO₂), commonly with iron-oxide and clay inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; opaque brown, rust-red, and tan with rounded orbicular patterns; waxy to vitreous luster; cryptocrystalline, with no visible cleavage and conchoidal fracture. The smooth surface indicates natural water-worn or polished material.

Identified September 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Silica-rich volcanic or sedimentary material was altered and cemented, while iron- and manganese-rich fluids produced the concentric orbs; precise age and locality cannot be determined from the image. Orbicular jasper commonly forms in volcanic environments and ancient hydrothermal systems.

Uses & applications

Used for cabochons, beads, tumbled stones, carvings, and ornamental objects; attractive patterned pieces are popular with collectors.

Geological facts

Orbicular jasper is often marketed as ocean jasper, though true Ocean Jasper is locality-specific, especially from Madagascar. Patterning varies dramatically between specimens.

Field identification & locations

Identify it by its opaque chalcedony-like body and rounded, ringed orbs; it is denser and harder than ordinary mudstone. Common sources include Madagascar, Mexico, Australia, Indonesia, and the western United States.