mineral
Polished orbicular jasper (likely ocean jasper)
Siliceous microcrystalline quartz/chalcedony with iron-oxide and volcanic inclusions; commonly called ocean jasper
AI-generated identification · may be incorrectMohs hardness 6.5–7; opaque, multicolored green, orange, yellow, blue, and red patterns with a waxy to vitreous polish. It consists mainly of cryptocrystalline quartz, with no visible cleavage and moderate-to-high specific gravity (~2.6).
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Physical properties
Mohs hardness 6.5–7; opaque, multicolored green, orange, yellow, blue, and red patterns with a waxy to vitreous polish. It consists mainly of cryptocrystalline quartz, with no visible cleavage and moderate-to-high specific gravity (~2.6).
Formation & geological history
Formed when silica-rich fluids silicified volcanic rock and produced orbicular or brecciated patterns, with iron and other minerals creating the colors. Ocean jasper is chiefly associated with Miocene-age volcanic rocks of Madagascar, though similar orbicular jaspers occur elsewhere.
Uses & applications
Used for cabochons, spheres, beads, carvings, and decorative objects; its value is primarily ornamental and collectible rather than industrial.
Geological facts
The spherical shape is human-made by grinding and polishing; the vivid patterning is natural but may be enhanced by the polish. “Ocean jasper” is a trade name, not a formally distinct mineral species.
Field identification & locations
Identify it by its opaque silica-rich body, hardness, lack of cleavage, and intricate orbicular/brecciated pattern; it should resist scratching by a steel knife. Common sources include Madagascar, Mexico, Australia, and the western United States.
