Rock Identifier
Tumbled yellow chalcedony (likely citrine-like quartz or yellow jasper) (Microcrystalline quartz, SiO₂; exact identification requires testing) — mineral
mineral

Tumbled yellow chalcedony (likely citrine-like quartz or yellow jasper)

Microcrystalline quartz, SiO₂; exact identification requires testing

AI-generated identification · may be incorrect

Honey-yellow, translucent to opaque, waxy-to-glassy luster, irregular internal pattern, and no visible cleavage; Mohs hardness about 6.5–7, specific gravity ~2.6. The smoothly rounded shape indicates tumbling or polishing.

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Physical properties

Honey-yellow, translucent to opaque, waxy-to-glassy luster, irregular internal pattern, and no visible cleavage; Mohs hardness about 6.5–7, specific gravity ~2.6. The smoothly rounded shape indicates tumbling or polishing.

Formation & geological history

Chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; yellow color may result from iron staining or inclusions. The specimen’s geological age cannot be determined visually and depends on its host deposit.

Uses & applications

Used as a low-cost lapidary stone, cabochon, carving material, and decorative collectible; it is not typically used as a major construction aggregate.

Geological facts

Yellow chalcedony, yellow jasper, heat-treated amethyst, and dyed quartz can look similar. Strong translucency and conchoidal fracture favor chalcedony, while an opaque, earthy appearance favors jasper.

Field identification & locations

Common sources include Brazil, Uruguay, Madagascar, India, and the United States. Check hardness against glass, inspect translucency, and use a specific-gravity or gemological test; avoid destructive tests on polished pieces.