metamorphic
Polished jasper
Microcrystalline quartz (SiO₂), commonly with iron-oxide and clay inclusions
AI-generated identification · may be incorrectTypically opaque, reddish-brown, cream, and golden, with waxy to vitreous luster and no visible crystals; hardness about 6.5–7 Mohs, conchoidal fracture, and specific gravity near 2.6. The rounded shape indicates tumbling and polishing.
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Physical properties
Typically opaque, reddish-brown, cream, and golden, with waxy to vitreous luster and no visible crystals; hardness about 6.5–7 Mohs, conchoidal fracture, and specific gravity near 2.6. The rounded shape indicates tumbling and polishing.
Formation & geological history
Jasper forms when silica-rich fluids replace or cement volcanic ash, sediments, or altered rock, with iron oxides producing red and brown coloration. Deposits occur in many ages, from Precambrian to recent hydrothermal and sedimentary environments.
Uses & applications
Used for cabochons, beads, carvings, decorative objects, and inexpensive lapidary specimens; rarely used as aggregate or ornamental stone in architecture.
Geological facts
The cream-and-red brecciated or flowing pattern may indicate brecciated jasper, picture jasper, or a related iron-rich chert. Exact variety cannot be confirmed from the photograph alone.
Field identification & locations
Identify it by its opaque patterned body, quartz-like hardness, lack of cleavage, and ability to scratch glass; it should not fizz in dilute hydrochloric acid. Common sources include India, Madagascar, Brazil, Australia, Mexico, and the western United States.
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