mineral

Tumbled brown chalcedony/jasper

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony or jasper

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, opaque to weakly translucent, brown/tan with earthy iron-oxide staining, and a waxy to dull luster; lacks visible cleavage and has a cryptocrystalline quartz structure.

Identified August 24, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or fractures, later acquiring brown coloration from iron oxides; the specimen appears mechanically tumbled and polished rather than naturally weathered. Age cannot be determined from the image.

Uses & applications

Used as a lapidary material for cabochons, beads, carvings, and decorative stones; common pieces have modest collector value.

Geological facts

Jasper is opaque and commonly patterned, while chalcedony is more translucent; this specimen may represent an overlap or iron-stained chalcedony rather than a precisely identifiable variety.

Field identification & locations

Commonly found in volcanic terrains, sedimentary silica deposits, and gravel beds worldwide. A glassy or waxy surface, quartz-like hardness, and inability to scratch it with a steel knife support identification; acid does not react.