mineral

Tumbled yellow jasper or chalcedony

Microcrystalline quartz, SiO₂; likely iron-oxide-bearing jasper/chalcedony

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque to slightly translucent, mustard-yellow to honey-brown, with a smooth polished surface and vitreous-to-waxy luster. Quartz has a trigonal crystal structure, but this specimen is microcrystalline and shows no visible cleavage.

Identified August 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids fill cavities or replace older rock, with iron oxides producing the yellow-brown color; age depends on its source deposit. The rounded shape is human-made by tumbling and polishing.

Uses & applications

Used as an inexpensive ornamental stone, cabochon, bead, and decorative object; not typically used in construction. Common tumbled pieces usually have modest collector value.

Geological facts

Jasper is an opaque variety of chalcedony, while more translucent material may be classified as yellow chalcedony or silicified rock. Color zoning and iron staining are common.

Field identification & locations

Identify by its glassy/waxy polish, lack of cleavage, fine-grained texture, and ability to scratch glass; a steel blade should not scratch it easily. Common sources include Brazil, Madagascar, India, Uruguay, and the western United States.