mineral

Polished ocean jasper (orbicular jasper)

Microcrystalline quartz (SiO₂) with hematite/goethite and other iron-rich inclusions

AI-generated identification · may be incorrect

A polished, opaque to slightly translucent chalcedony specimen with brick-red, cream, gray-blue, and pale orbicular patterns; vitreous to waxy luster and conchoidal fracture. Quartz hardness is about 6.5–7 Mohs; cleavage is absent, and specific gravity is approximately 2.6.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms from silica-rich volcanic fluids filling cavities and fractures, with iron oxides and other minerals producing the colors and orbs. Classic ocean jasper formed in Miocene volcanic rocks of Madagascar, roughly 5–23 million years ago.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and lapidary collections; it is not generally used as a structural material.

Geological facts

“Ocean jasper” is a trade name, and true orbicular material is strongly associated with Madagascar’s coastal deposits. The visible pattern reflects concentric mineral growth rather than fossils.

Field identification & locations

Identify it by its opaque red groundmass, rounded orbicular markings, and hardness sufficient to scratch glass; dyed or imitation jasper may show unnaturally uniform color. Common sources include Madagascar, Australia, Mexico, and the western United States.