mineral

Polished carnelian/chalcedony

Microcrystalline quartz (SiO₂), reddish iron-bearing chalcedony

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent reddish-brown to orange, waxy-to-glassy luster, cryptocrystalline structure, no visible cleavage, specific gravity about 2.60. The smooth glossy surface indicates tumbling or polishing.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron oxides producing the red-brown color; commonly associated with volcanic rocks, generally formed from Paleozoic to younger deposits.

Uses & applications

Used for beads, cabochons, carvings, seals, and inexpensive jewelry; also collected as an ornamental stone.

Geological facts

Carnelian is a variety of chalcedony, and its color may deepen through gentle heating or dyeing. The specimen may also be brown sard or iron-stained agate, since the image lacks diagnostic banding.

Field identification & locations

Identify by its even translucent red-orange/brown color, waxy luster, very high toughness, and ability to scratch glass. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.