metamorphic
Tumbled ocean jasper (orbicular jasper), likely brecciated variety
Jasper: microcrystalline quartz (SiO₂) with iron-oxide staining and other silicate inclusions
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; opaque white to cream with orange-red, irregular iron-oxide patches; dull to waxy luster and no visible cleavage. Dense, fine-grained, cryptocrystalline quartz with conchoidal fracture; the rounded shape is human-tumbled.
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Physical properties
Hardness about 6.5–7 Mohs; opaque white to cream with orange-red, irregular iron-oxide patches; dull to waxy luster and no visible cleavage. Dense, fine-grained, cryptocrystalline quartz with conchoidal fracture; the rounded shape is human-tumbled.
Formation & geological history
Forms when silica-rich fluids cement and replace volcanic ash or breccia, with iron oxides producing the red-orange coloration; many ocean jasper deposits formed in ancient volcanic rocks, commonly associated with Paleoproterozoic–Neoproterozoic terranes. The exact locality cannot be confirmed from the image.
Uses & applications
Used for cabochons, beads, carvings, polished stones, and decorative objects; attractive pieces are popular among collectors but are generally inexpensive.
Geological facts
Jasper is a variety of chalcedony/microcrystalline quartz rather than a single mineral species. “Ocean jasper” is a trade name commonly applied to orbicular or patterned jasper from Madagascar.
Field identification & locations
Identify it by its opaque silica-rich body, hardness, waxy polish, and red-orange iron staining; it should scratch glass but not be scratched by a steel knife. Common jasper occurs worldwide, especially in volcanic regions.
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