mineral

Tumbled yellow chalcedony

Microcrystalline quartz (SiO₂), likely yellow chalcedony or low-grade citrine-like quartz

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; translucent honey-yellow to gray, waxy-to-glassy luster, cryptocrystalline structure, no visible cleavage, and specific gravity near 2.6. The rounded shape indicates natural or human tumbling/polishing.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; its age depends on the host deposit, ranging from relatively recent to hundreds of millions of years. Yellow color may come from iron staining or inclusions.

Uses & applications

Used for beads, cabochons, carvings, decorative stones, and inexpensive gemstone jewelry; larger chalcedony masses are occasionally ornamental material.

Geological facts

It may be confused with yellow jasper, yellow calcite, amber, or glass. Quartz should resist scratching by a steel knife, whereas calcite is much softer and amber is very light and warm to the touch.

Field identification & locations

Common in volcanic regions and alluvial gravels worldwide, including Brazil, Uruguay, India, Madagascar, and the western United States. A glassy conchoidal fracture and quartz hardness support identification; laboratory testing is needed for certainty.