mineral

Tumbled yellow jasper or serpentine

Jasper: microcrystalline quartz (SiO₂); possible serpentine: Mg₃Si₂O₅(OH)₄

AI-generated identification · may be incorrect

Opaque, mustard-yellow to olive-brown, smoothly tumbled with a waxy to subvitreous luster; likely hardness about 4–7 Mohs depending on composition. The image alone cannot reliably distinguish jasper from yellow serpentine or another polished stone.

Identified August 7, 2026More mineral →

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Physical properties

Formation & geological history

Jasper forms when silica-rich fluids replace or cement volcanic and sedimentary material; serpentine forms by hydrothermal alteration of magnesium-rich ultramafic rocks. These processes range from ancient Precambrian settings to geologically recent alteration zones.

Uses & applications

Used as an inexpensive lapidary, ornamental, and metaphysical stone; tumbled pieces are commonly sold for a few dollars.

Geological facts

The rounded shape and glossy surface indicate human tumbling and polishing rather than a natural crystal form. A glassy scratch resistance and no obvious cleavage would favor jasper.

Field identification & locations

Common sources include India, Madagascar, Brazil, Australia, and the western United States. Test cautiously: jasper should resist scratching by a steel file, while softer serpentine may scratch more readily; streak and hardness tests are more diagnostic than color.