mineral
Tumbled jasper/chalcedony
Microcrystalline quartz (SiO₂), likely brecciated or iron-stained jasper
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; opaque cream to tan body with reddish-brown iron-oxide veining and earthy, waxy-to-dull luster. Quartz is trigonal, lacks visible cleavage, and has conchoidal fracture; specific gravity is approximately 2.6.
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Physical properties
Hardness about 6.5–7 Mohs; opaque cream to tan body with reddish-brown iron-oxide veining and earthy, waxy-to-dull luster. Quartz is trigonal, lacks visible cleavage, and has conchoidal fracture; specific gravity is approximately 2.6.
Formation & geological history
Silica-rich groundwater deposited chalcedony and jasper in cavities or fractures, with later iron-oxide staining producing the red-brown patterns; the exact geological age and locality cannot be determined from the image.
Uses & applications
Used as inexpensive cabochons, beads, tumbled stones, carvings, and decorative objects; valued mainly for color and pattern rather than rarity.
Geological facts
The rounded shape and glossy surface indicate human tumbling and polishing. “Jasper” is a trade term for opaque, impure chalcedony or microcrystalline quartz.
Field identification & locations
Identify it by its opaque fine-grained texture, glassy/waxy polish, hardness, and absence of cleavage; it should scratch glass but not be scratched by a steel knife. Similar material occurs worldwide, including the United States, Mexico, Brazil, Madagascar, and Australia.
