sedimentary

Polished Ocean Jasper (likely orbicular jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron oxides and other accessory minerals

AI-generated identification · may be incorrect

Typically opaque, multicolored gray, cream, orange, and red with orbicular patterns; vitreous to waxy luster, cryptocrystalline structure, no visible cleavage, and Mohs hardness about 6.5–7. Specific gravity is approximately 2.6.

Identified August 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms from silica-rich volcanic or sedimentary fluids that cement and replace rock, with iron and other minerals creating the patterns; many “Ocean Jasper” varieties formed in Oligocene–Miocene volcanic environments of Madagascar. The specimen appears tumbled and polished.

Uses & applications

Used for cabochons, beads, carvings, decorative objects, and lapidary collections; its durability makes it suitable for jewelry but not usually structural construction.

Geological facts

Orbicular jasper is prized for concentric “eye” or sphere-like markings, though this piece’s pattern may also be brecciated or mossy jasper rather than true Ocean Jasper.

Field identification & locations

Identify by its opaque hardness, multicolored silica body, and lack of cleavage; it should resist scratching by a steel knife but be scratched by quartz. Common sources include Madagascar, Indonesia, Mexico, and the western United States.