mineral
Tumbled jasper, likely red/brown jasper
Microcrystalline quartz (chalcedony), mainly SiO₂, colored by iron oxides
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; opaque reddish-brown with darker bands, earthy to waxy luster, and no visible cleavage. It appears rounded and polished/tumbled, with a dense cryptocrystalline structure.
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Physical properties
Hardness about 6.5–7 Mohs; opaque reddish-brown with darker bands, earthy to waxy luster, and no visible cleavage. It appears rounded and polished/tumbled, with a dense cryptocrystalline structure.
Formation & geological history
Jasper forms when silica-rich fluids replace or cement volcanic ash, sediments, or rock cavities; iron oxides produce the red-brown color. The exact geological age cannot be determined from the photograph.
Uses & applications
Used for cabochons, beads, carvings, tumbling, lapidary ornaments, and inexpensive collectible specimens; it has little structural or industrial value.
Geological facts
Jasper is a variety of chalcedony and is often grouped with quartz despite lacking visible crystals. Brown banding may indicate brecciation, iron-rich layers, or another jasper variety.
Field identification & locations
Identify it by its opaque red-brown body, very fine texture, lack of cleavage, and ability to scratch ordinary glass; an unglazed ceramic streak test should be white to faint reddish. Common sources include India, Brazil, Madagascar, Australia, Mexico, and the western United States.
