Rock Identifier
Tumbled red jasper (Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides) — mineral
mineral

Tumbled red jasper

Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides

AI-generated identification · may be incorrect

Opaque brick-red to brown, with mottled cream/gray matrix; dull to waxy luster and no visible crystals. Mohs hardness about 6.5–7, conchoidal fracture, massive structure, and specific gravity around 2.5–2.9; rounded surfaces indicate natural or artificial tumbling.

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Physical properties

Opaque brick-red to brown, with mottled cream/gray matrix; dull to waxy luster and no visible crystals. Mohs hardness about 6.5–7, conchoidal fracture, massive structure, and specific gravity around 2.5–2.9; rounded surfaces indicate natural or artificial tumbling.

Formation & geological history

Forms when silica-rich fluids replace or cement volcanic ash, sediments, or other rock, with hematite/goethite producing the red color. Deposits occur in many ages, commonly in volcanic or sedimentary environments.

Uses & applications

Used for cabochons, beads, carvings, decorative stone, and lapidary specimens; occasionally used as aggregate or architectural accent stone.

Geological facts

Jasper is a variety of chalcedony or microcrystalline quartz, though its opaque, impurity-rich composition distinguishes it from translucent agate. The small hole may be a natural vesicle, weathering cavity, or drilling mark.

Field identification & locations

Identify it by its opaque red color, fine-grained texture, iron staining, high hardness, and inability to scratch with a steel knife easily; it should scratch glass. Common sources include India, Madagascar, Brazil, Australia, and the western United States.