metamorphic

Tumbled orbicular jasper

Orbicular jasper, chiefly microcrystalline quartz (SiO₂) with iron oxides and other silicates

AI-generated identification · may be incorrect

Typically opaque brown, black, cream, and reddish with rounded orbicular patterns; waxy to vitreous luster, no visible cleavage, Mohs hardness about 6.5–7, and specific gravity around 2.5–2.8. The smooth surface indicates human tumbling/polishing.

Identified September 3, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms from silica-rich volcanic or hydrothermal material in which concentric mineral growth creates orbicules, later altered and silicified. Deposits are generally Precambrian to younger, depending on locality; exact age cannot be determined from the image.

Uses & applications

Used for cabochons, beads, carvings, paperweights, and decorative objects; valued mainly as an ornamental lapidary stone rather than for construction.

Geological facts

Orbicular jasper is often marketed under locality names such as ocean jasper, although true ocean jasper has distinctive radiating orbicules and comes chiefly from Madagascar.

Field identification & locations

Identify it by its opaque jasper body, rounded contrasting orbs, quartz-like hardness, and inability to scratch with a steel knife easily; common sources include Madagascar, Mexico, Australia, and the western United States. A locality cannot be confirmed visually.