mineral
Tumbled yellow-green chalcedony or serpentine
Microcrystalline quartz (SiO₂), possibly chrysoprase; alternative: serpentine-group mineral
AI-generated identification · may be incorrectTranslucent yellow-green, smooth tumbled surface, vitreous-to-waxy luster, no obvious cleavage, and likely hardness about 6.5–7 if chalcedony (lower, about 2.5–5.5, if serpentine). The image alone cannot reliably distinguish these possibilities.
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Physical properties
Translucent yellow-green, smooth tumbled surface, vitreous-to-waxy luster, no obvious cleavage, and likely hardness about 6.5–7 if chalcedony (lower, about 2.5–5.5, if serpentine). The image alone cannot reliably distinguish these possibilities.
Formation & geological history
Chalcedony forms when silica-rich fluids fill cavities and fractures, commonly in volcanic rocks; serpentine forms by hydration and alteration of ultramafic rocks. Both are geologically ancient and occur in many environments.
Uses & applications
Used as a lapidary stone, cabochon, bead, or inexpensive collectible; chrysoprase-quality material can be used in jewelry. Serpentine is also used decoratively and occasionally as a carving stone.
Geological facts
The yellow-green color may result from nickel-bearing minerals, iron staining, or coloration of a processed specimen. It appears natural rather than manufactured, but identification requires testing.
Field identification & locations
Check hardness with a steel knife or quartz point, streak, translucency, and specific gravity; chalcedony resists scratching by steel, whereas serpentine usually does not. Common sources include Brazil, India, Madagascar, Australia, and the United States.
