mineral

Tumbled yellow-orange chalcedony (possibly yellow jasper)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide coloration

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque to slightly translucent, waxy-to-dull luster, pale yellow-orange color with reddish staining, and no visible cleavage. Its rounded shape and smooth surface indicate tumbling or natural water abrasion.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich groundwater deposited microcrystalline quartz in cavities or fractures, with iron oxides producing the warm color; such material commonly formed in volcanic rocks during the Cenozoic or older hydrothermal episodes.

Uses & applications

Used as a lapidary stone for tumbled specimens, cabochons, carvings, and inexpensive jewelry; also collected as decorative material.

Geological facts

Chalcedony is quartz composed of extremely fine interlocking crystals, so individual crystals are usually invisible. The specimen could also be a jasper variety if fully opaque and more granular.

Field identification & locations

Check for glassy hardness: it should scratch ordinary window glass but not quartz. Common sources include Brazil, Madagascar, India, Uruguay, and the western United States; acid testing is unnecessary.