Rock Identifier
Polished brecciated jasper (Jasper, an opaque microcrystalline variety of quartz (SiO₂), with iron-oxide-rich breccia fragments and cement) — sedimentary
sedimentary

Polished brecciated jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), with iron-oxide-rich breccia fragments and cement

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, opaque, with red-brown hematite/goethite coloring and cream to gray angular inclusions; vitreous to waxy luster and no visible cleavage. The rounded, glossy surface indicates tumbling and polishing.

Identified More sedimentary
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Physical properties

Typically Mohs hardness 6.5–7, opaque, with red-brown hematite/goethite coloring and cream to gray angular inclusions; vitreous to waxy luster and no visible cleavage. The rounded, glossy surface indicates tumbling and polishing.

Formation & geological history

Forms when silica-rich fluids cement silicified, fractured volcanic or sedimentary material, commonly during hydrothermal alteration. Its age varies widely by deposit, often Paleozoic to Cenozoic.

Uses & applications

Used for cabochons, beads, carvings, paperweights, and ornamental objects; attractive pieces are popular among collectors but generally modestly priced.

Geological facts

The angular contrasting fragments distinguish brecciated jasper from uniformly colored red jasper; iron oxides produce the red coloration.

Field identification & locations

Identify it by its opaque red matrix, cream angular clasts, glassy polish, and inability to scratch with a copper coin; quartz or steel can scratch it. Common sources include Brazil, Madagascar, India, Mexico, and the western United States.