metamorphic
Polished/tumbled iron-rich jasper (likely brecciated jasper)
Jasper, microcrystalline quartz (SiO₂) colored chiefly by iron oxides/hydroxides
AI-generated identification · may be incorrectOpaque brown-gold stone with reddish iron staining, waxy to vitreous luster, and a visible healed fracture or brecciation. Mohs hardness is approximately 6.5–7; quartz has no cleavage and a specific gravity near 2.6.
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Physical properties
Opaque brown-gold stone with reddish iron staining, waxy to vitreous luster, and a visible healed fracture or brecciation. Mohs hardness is approximately 6.5–7; quartz has no cleavage and a specific gravity near 2.6.
Formation & geological history
Forms when silica-rich groundwater cements and replaces volcanic or sedimentary material, with iron minerals producing the ochre coloration; individual deposits may range from Precambrian to much younger. Tumbled polishing has rounded the specimen and enhanced its surface.
Uses & applications
Used as decorative stone, lapidary material, cabochons, beads, carvings, and inexpensive collectibles; occasionally used for ornamental tiles or accents.
Geological facts
Jasper is technically a dense, opaque variety of chalcedony or microcrystalline quartz. The irregular pale line likely represents a natural crack filled or sealed by later silica.
Field identification & locations
Identify by its opaque appearance, strong hardness, nonmetallic waxy sheen, and inability to scratch it with a steel knife easily; common sources include the western United States, Australia, Brazil, India, and Madagascar. A streak test on unglazed porcelain may show little or a yellow-brown streak.
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