igneous
Brecciated jasper (likely ocean jasper or rhyolitic jasper)
Silica-rich volcanic breccia; predominantly microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and clay/mineral inclusions
AI-generated identification · may be incorrectTypically hardness 6.5–7, opaque, reddish-brown with lavender, cream, and white angular patches or veins; waxy to dull luster and no obvious cleavage. The white material is likely chalcedony or quartz, while red coloration commonly comes from iron oxides.
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Physical properties
Typically hardness 6.5–7, opaque, reddish-brown with lavender, cream, and white angular patches or veins; waxy to dull luster and no obvious cleavage. The white material is likely chalcedony or quartz, while red coloration commonly comes from iron oxides.
Formation & geological history
Forms when silica-rich volcanic fragments are cemented and later filled or replaced by chalcedony and quartz in gas cavities or fractures. Exact age and locality cannot be determined from the photograph; many such specimens are Cenozoic volcanic material.
Uses & applications
Used as ornamental stone, cabochons, beads, carvings, polished slabs, and decorative objects; attractive pieces are collected as jasper or ocean jasper.
Geological facts
The contrasting angular fragments and pale vein networks indicate brecciation rather than uniform jasper. A polished surface would reveal the pattern more clearly.
Field identification & locations
Commonly found in volcanic terrains, especially Madagascar, Oregon, Idaho, Utah, Mexico, and Australia. Confirm with a fresh surface, hardness test against glass, and inspection for quartz-like conchoidal fracture; identification is visual and locality-dependent.
