Rock Identifier
Red jasper (likely brecciated jasper) (Microcrystalline quartz/chalcedony, SiO₂, colored mainly by iron oxides) — mineral
mineral

Red jasper (likely brecciated jasper)

Microcrystalline quartz/chalcedony, SiO₂, colored mainly by iron oxides

AI-generated identification · may be incorrect

Opaque reddish-brown with cream and gray patches, earthy to dull luster, and irregular fracture; quartz hardness is about 6.5–7 Mohs, with no cleavage. The texture appears massive and fine-grained, possibly brecciated or naturally patterned.

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Physical properties

Opaque reddish-brown with cream and gray patches, earthy to dull luster, and irregular fracture; quartz hardness is about 6.5–7 Mohs, with no cleavage. The texture appears massive and fine-grained, possibly brecciated or naturally patterned.

Formation & geological history

Jasper forms when silica-rich fluids replace or cement sediment and volcanic material, while iron oxides produce the red coloration. It commonly forms in volcanic or hydrothermal environments over broad Precambrian-to-younger geological ages.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary specimens; occasionally used as decorative stone. It has little industrial value compared with ordinary quartz.

Geological facts

Red jasper is a variety of opaque chalcedony rather than a single formally distinct mineral species. The cream-colored zones may represent quartz-rich veins or altered host material.

Field identification & locations

Identify it by its opaque red color, very fine quartz texture, hardness, and lack of visible cleavage; it should scratch glass but not be scratched by a steel knife. Common sources include India, Brazil, Madagascar, Uruguay, the United States, and Australia.