mineral
Polished ocean jasper (orbicular jasper)
Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and other mineral inclusions
AI-generated identification · may be incorrectTypically Mohs 6.5–7; cream, yellow, orange, red, green, or brown with orbicular patterns, opaque to translucent, and a glassy-to-waxy luster. This rounded, polished specimen shows pale chalcedony with dark inclusions and iron staining; exact identification from the blurred image is uncertain.
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Physical properties
Typically Mohs 6.5–7; cream, yellow, orange, red, green, or brown with orbicular patterns, opaque to translucent, and a glassy-to-waxy luster. This rounded, polished specimen shows pale chalcedony with dark inclusions and iron staining; exact identification from the blurred image is uncertain.
Formation & geological history
Forms when silica-rich volcanic material is replaced or cemented by chalcedony, commonly producing spherical mineral-growth patterns. 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 decorative objects; it has little industrial value as aggregate.
Geological facts
“Ocean jasper” is a trade name, not a single officially defined mineral species. Orbicular patterns may result from concentric growth, replacement, or radiating fibrous chalcedony.
Field identification & locations
Identify by its very hard, non-cleaving silica body, waxy/glassy polish, and rounded orbicular markings; it should scratch glass but not be scratched by a steel knife. Common sources include Madagascar, Mexico, Australia, and Indonesia.
