metamorphic
Polished orbicular jasper (likely ocean or leopard jasper)
Silica-rich microcrystalline quartz/chalcedony with iron-oxide and other mineral inclusions; SiO₂-dominant
AI-generated identification · may be incorrectTypically hardness 6.5–7 Mohs, opaque, with a waxy to vitreous luster and brown, gold, cream, and gray orbicular patterns. It has cryptocrystalline quartz structure, no visible cleavage, and specific gravity around 2.5–2.7.
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Physical properties
Typically hardness 6.5–7 Mohs, opaque, with a waxy to vitreous luster and brown, gold, cream, and gray orbicular patterns. It has cryptocrystalline quartz structure, no visible cleavage, and specific gravity around 2.5–2.7.
Formation & geological history
Forms when silica-rich volcanic or sedimentary material is replaced and cemented by chalcedony/quartz, with contrasting inclusions producing the orbicular pattern; specimens are generally Cenozoic to older, depending on locality.
Uses & applications
Commonly cut and polished for cabochons, beads, carvings, worry stones, and decorative objects; it has little industrial use beyond ornamental stone.
Geological facts
Orbicular markings are mineral-filled textures rather than true fossils or concentric crystal growth. The pictured piece appears tumbled or smoothly polished, exposing contrasting chalcedony-rich patches.
Field identification & locations
Identify it by its opaque silica body, glassy/waxy polish, lack of cleavage, and distinctive rounded patches; common sources include Madagascar, Mexico, Australia, and the western United States. A steel file should not easily scratch it, while quartz will not scratch it readily.
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