mineral

Polished Ocean Jasper (likely)

Silicified orbicular rhyolite; primarily microcrystalline quartz (SiO₂)

AI-generated identification · may be incorrect

Tumbled, opaque reddish-brown stone with pale green-gray patches and minor dark inclusions; vitreous to waxy luster. Quartz hardness is about 6.5–7 Mohs, with no obvious cleavage; density commonly 2.5–2.7 g/cm³.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich volcanic fluids silicify rhyolitic rock, often preserving orbicular or brecciated textures. Ocean jasper is chiefly associated with Oligocene–Miocene volcanic rocks of northwestern Madagascar.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and collector specimens; its value is mainly ornamental rather than industrial.

Geological facts

The name “Ocean Jasper” is a trade name for attractive orbicular or patterned jasper, not a single mineral species. The distinctive color patches reflect iron oxides, chlorite, and other altered volcanic minerals.

Field identification & locations

Identify it by opaque chalcedonic silica, strong polish, irregular multicolor patterns, and inability to scratch with a steel knife; glass may scratch similarly, so a streak or hardness test helps. Comparable jasper occurs worldwide, while classic ocean jasper is from Madagascar.