gemstone

Tumbled carnelian (red-orange chalcedony)

Carnelian, a cryptocrystalline variety of quartz (SiO₂), commonly colored by iron oxides

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent reddish brown to orange, vitreous-to-waxy luster, no visible crystals, and conchoidal fracture. It is commonly tumbled and polished, producing the smooth rounded surface shown.

Identified September 17, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, with iron impurities creating the red color; deposits range from ancient to relatively young. Common sources include India, Brazil, Uruguay, Madagascar, and parts of the United States.

Uses & applications

Used for beads, cabochons, carvings, worry stones, and inexpensive jewelry; historically valued as an ornamental stone and seal material.

Geological facts

Carnelian is a member of the agate/chalcedony family; darker red material may be heat-treated or dyed. Its color can vary from honey orange to deep brownish red.

Field identification & locations

Identify it by its uniform translucent red-orange color, hardness, waxy polish, and lack of cleavage; it should scratch glass but not quartz. Common specimens usually sell for $2–$15, while larger, vividly colored natural pieces may bring $20–$75.