mineral

Tumbled green stone, likely serpentine or green jasper

Probable serpentine-group mineral (Mg₃Si₂O₅(OH)₄) or microcrystalline quartz/chalcedony

AI-generated identification · may be incorrect

Small polished, rounded pebble with dark green and brown coloration, mottled pattern, and waxy to subdued vitreous luster. Serpentine is Mohs 2.5–4; jasper/chalcedony is harder, about Mohs 6.5–7; the image alone cannot distinguish them reliably.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Serpentine forms when ultramafic rocks are hydrated during metamorphism; green jasper forms from silica-rich volcanic or sedimentary fluids. These materials range from ancient Precambrian to much younger geological settings.

Uses & applications

Commonly sold as inexpensive tumbled stones, carvings, beads, and decorative objects; some serpentine is used as ornamental stone, while jasper is used in jewelry and lapidary work.

Geological facts

The rounded shape and glossy surface indicate human tumbling and polishing rather than natural outcrop weathering.

Field identification & locations

Test hardness: a steel nail may scratch serpentine but should not scratch jasper; quartz will scratch glass. Common sources include California, New Zealand, Italy, India, Brazil, and Madagascar.