mineral

Tumbled ocean jasper

Orbicular jasper (microcrystalline quartz, SiO₂)

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque reddish-brown, cream, mustard, and gray banding/orbicular patterns; vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage. Specific gravity is approximately 2.6.

Identified September 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica-rich fluids cemented or replaced volcanic rock, producing chalcedony, quartz, and iron-oxide patterns; most classic material is Oligocene–Miocene age from Madagascar. The rounded shape and sheen indicate mechanical tumbling and polishing.

Uses & applications

Used as a decorative stone, cabochons, beads, carvings, and collector specimens; not generally used as structural stone because it is typically sold in small pieces.

Geological facts

“Ocean jasper” is a trade name rather than a single rigorously defined mineral species; orbicular patterns are its signature feature. The best-known deposits occur along Madagascar’s remote northwest coast.

Field identification & locations

Identify by its opaque silica-rich body, concentric or flowing orbicular bands, hardness, and resistance to scratching by steel; it should not fizz in dilute acid. Common sources include Madagascar, Australia, Mexico, and parts of the western United States.