mineral

Tumbled yellow jasper (probable)

Microcrystalline quartz/chalcedony, SiO₂, colored by iron oxides

AI-generated identification · may be incorrect

Opaque mustard-yellow to ochre, smoothly rounded and lightly waxy; Mohs hardness about 6.5–7, no visible cleavage, conchoidal fracture, and specific gravity around 2.6. The image alone cannot confirm composition; it could also be yellow chert or iron-stained quartzite.

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace or fill cavities in volcanic or sedimentary rocks, with iron producing the yellow-brown color; deposits range from Paleozoic to recent. The rounded surface indicates human tumbling or natural abrasion.

Uses & applications

Used for cabochons, beads, carvings, lapidary pieces, and decorative stone; occasionally used as a minor aggregate or facing stone. Common tumbled pieces have little individual collector premium.

Geological facts

Jasper is an opaque variety of chalcedony, unlike transparent quartz varieties such as citrine. Color zoning, brecciation, or orbicular patterns can increase desirability.

Field identification & locations

Commonly found in volcanic terrains and silica-rich sedimentary formations, including parts of the western United States, Mexico, Australia, and Madagascar. A glass-scratching test and lack of cleavage support quartz, but acid and hardness tests should be performed cautiously.