mineral

Brecciated jasper with quartz/chalcedony

Jasper (microcrystalline quartz, SiO₂), with chalcedony and iron-oxide matrix

AI-generated identification · may be incorrect

Opaque to translucent red-brown, gray, and cream fragments in a brecciated pattern; waxy to glassy luster, no obvious cleavage, conchoidal fracture, and Mohs hardness about 6.5–7. Quartz crystals may show vitreous luster; red coloration is commonly hematite or goethite.

Identified August 24, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids cement and replace fractured volcanic or sedimentary rock, with iron oxides producing the red-brown colors. Usually Cenozoic to older, depending on the host formation and locality.

Uses & applications

Used for lapidary cabochons, carvings, polished slabs, and ornamental objects; massive specimens are mainly valued by collectors rather than industry.

Geological facts

The angular color patches indicate brecciation rather than ordinary banding. The translucent gray areas may be chalcedony or quartz, while dark metallic-looking zones can be iron oxides or sulfides.

Field identification & locations

Identify by its hardness, opaque-to-translucent silica-rich body, irregular angular pattern, and resistance to scratching by steel; locality information or testing is needed to distinguish it from agate, rhyolite, or slag. Common in hydrothermal volcanic regions worldwide, including the western United States, Mexico, Madagascar, and Australia.