mineral
Tumbled red jasper
Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly colored by iron oxides
AI-generated identification · may be incorrectTypically Mohs 6.5–7; red to brick-red, opaque, with earthy to vitreous luster and no visible cleavage. The rounded, glossy surfaces indicate mechanical tumbling and polishing.
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Physical properties
Typically Mohs 6.5–7; red to brick-red, opaque, with earthy to vitreous luster and no visible cleavage. The rounded, glossy surfaces indicate mechanical tumbling and polishing.
Formation & geological history
Forms when silica-rich fluids replace or cement volcanic or sedimentary material, with iron producing the red color; deposits range from Precambrian to younger ages. Common sources include Brazil, India, Madagascar, Uruguay, and the western United States.
Uses & applications
Used for lapidary cabochons, beads, carvings, decorative objects, and inexpensive jewelry; polished pieces are also sold as collecting specimens.
Geological facts
Jasper is a variety of chalcedony/microcrystalline quartz, though its dense, opaque texture distinguishes it from translucent agate. Surface variation and occasional dark veins reflect changing iron and silica content during formation.
Field identification & locations
Identify it by its opaque red color, fine texture, lack of cleavage, and quartz hardness; it should scratch glass but not be scratched by a steel knife. The surrounding material appears to be granite, while the pictured rounded specimens are polished pebbles.
