Rock Identifier
Tumbled brecciated jasper (Jasper, microcrystalline quartz (SiO₂), commonly with iron oxides and chalcedony) — mineral
mineral

Tumbled brecciated jasper

Jasper, microcrystalline quartz (SiO₂), commonly with iron oxides and chalcedony

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque, brown-red, cream, gray, and black coloration; vitreous to waxy luster; cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded shape and smooth surface indicate tumbling or polishing.

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Physical properties

Hardness about 6.5–7 Mohs; opaque, brown-red, cream, gray, and black coloration; vitreous to waxy luster; cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded shape and smooth surface indicate tumbling or polishing.

Formation & geological history

Jasper forms when silica-rich fluids replace or cement volcanic ash, sediments, or brecciated rock, with iron producing red-brown colors. Deposits range from Precambrian to relatively young volcanic and sedimentary settings.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary collections; occasionally used as decorative stone. Common polished pieces typically sell for $5–$25, while larger or unusually patterned specimens may reach $30–$75.

Geological facts

The specimen appears brecciated or orbicular, with angular dark fragments and rounded cream-to-reddish zones cemented by chalcedony. Jasper is technically a rock rather than a single mineral species.

Field identification & locations

Identify it by its opaque patterned body, quartz-like hardness, lack of cleavage, and inability to scratch with a steel knife easily; it should scratch glass. Common sources include India, Madagascar, Brazil, Mexico, Australia, and the western United States.