mineral

Tumbled jasper or chalcedony

Microcrystalline quartz (SiO₂), likely brown jasper/chalcedony

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque to slightly translucent brown with cream veining, waxy to dull luster, and no visible cleavage. Its rounded shape indicates tumbling or natural abrasion.

Identified August 16, 2026More mineral →

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Physical properties

Hardness about 6.5–7 Mohs; opaque to slightly translucent brown with cream veining, waxy to dull luster, and no visible cleavage. Its rounded shape indicates tumbling or natural abrasion.

Formation & geological history

Forms when silica-rich groundwater fills cavities, fractures, or volcanic vesicles, later hardening into microcrystalline quartz; exact geological age cannot be determined from the image. Commonly associated with volcanic and sedimentary environments.

Uses & applications

Used for tumbled stones, cabochons, beads, carvings, and decorative objects; ordinary pieces have minimal commercial value.

Geological facts

Jasper is the opaque, impurity-rich variety of microcrystalline quartz, while chalcedony is generally more translucent. Brown coloration commonly results from iron oxides or hydroxides.

Field identification & locations

Identify it by its fine-grained appearance, lack of cleavage, glassy-to-waxy surface, and inability to scratch it with a steel knife; quartz should scratch ordinary glass. Common sources include Brazil, India, Madagascar, Mexico, and the western United States.