mineral

Tumbled chalcedony (likely orange agate/carnelian)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide coloration

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent honey-orange to cream, with waxy-to-glassy luster and no visible cleavage. Its rounded shape and polished surface indicate human tumbling; pale patches may be quartz, druzy, or matrix.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, often developing banding or iron staining; many deposits formed during the Cenozoic, though chalcedony occurs throughout geological time.

Uses & applications

Used for cabochons, beads, carvings, ornamental stone, and inexpensive jewelry; polished pieces are also popular as decorative and metaphysical specimens.

Geological facts

Carnelian is the orange-red variety of chalcedony, while agate is typically banded or patterned chalcedony; the boundary between the names can be informal.

Field identification & locations

Common in volcanic terrains and gravels worldwide, especially Brazil, Uruguay, India, Madagascar, and the western United States. A glassy/waxy surface, quartz-like hardness, translucency, and lack of cleavage help distinguish it from colored glass.