metamorphic
Brecciated jasper
Silica-rich cryptocrystalline quartz (SiO₂), commonly with iron-oxide and clay-rich matrix
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; opaque, angular multicolored fragments in a brown, red, yellow, and gray matrix; vitreous to dull luster, no visible cleavage, conchoidal to uneven fracture, and specific gravity around 2.5–2.7.
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Physical properties
Hardness about 6.5–7 Mohs; opaque, angular multicolored fragments in a brown, red, yellow, and gray matrix; vitreous to dull luster, no visible cleavage, conchoidal to uneven fracture, and specific gravity around 2.5–2.7.
Formation & geological history
Forms when silica-rich rock is fractured and the pieces are cemented by chalcedony, quartz, and iron oxides, often during hydrothermal activity or weathering. It may range from relatively young surficial deposits to Precambrian-hosted material, depending on locality.
Uses & applications
Used as ornamental stone, cabochons, beads, carvings, polished slabs, and small collectibles; occasionally used for decorative tile and veneer.
Geological facts
The angular clasts distinguish brecciated jasper from more uniformly patterned jasper or agate. Iron oxides produce the red, yellow, and brown coloration.
Field identification & locations
Identify it by its opaque appearance, sharp contrasting fragments, quartz-like hardness, and inability to scratch it with a steel knife easily. Common sources include Australia, Madagascar, India, Mexico, and the western United States.
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