Rock Identifier
Tumbled chalcedony (likely yellow-orange jasper or carnelian) (Microcrystalline quartz, SiO₂; potentially iron-stained chalcedony/jasper) — mineral
mineral

Tumbled chalcedony (likely yellow-orange jasper or carnelian)

Microcrystalline quartz, SiO₂; potentially iron-stained chalcedony/jasper

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; peach-orange, opaque to slightly translucent, with a waxy to dull luster and no visible cleavage. Its smooth rounded shape indicates natural water wear or tumbling; specific gravity is about 2.6.

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Physical properties

Hardness 6.5–7 Mohs; peach-orange, opaque to slightly translucent, with a waxy to dull luster and no visible cleavage. Its smooth rounded shape indicates natural water wear or tumbling; specific gravity is about 2.6.

Formation & geological history

Formed when silica-rich groundwater fills cavities or fractures, later colored by iron oxides; such material commonly formed in volcanic or sedimentary environments during various geologic ages. The specimen has been naturally or mechanically polished.

Uses & applications

Used as a lapidary stone, cabochon, carving material, and inexpensive collector specimen; similar jasper is also used for decorative objects and jewelry.

Geological facts

Chalcedony is quartz whose crystals are microscopic, producing a smooth waxy appearance. Stronger translucency and banding would suggest carnelian or agate, while fully opaque material is more consistent with jasper.

Field identification & locations

Common in volcanic terrains and gravel deposits worldwide, especially Brazil, India, Madagascar, Uruguay, and the western United States. A quartz hardness test, lack of cleavage, and translucent edges help distinguish it from softer calcite or plastic.