gemstone

Tumbled carnelian (likely)

Carnelian, orange-red variety of cryptocrystalline silica (SiO₂), chalcedony

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange to reddish-orange color, vitreous to waxy luster, and no visible crystal faces or cleavage. The rounded, glossy surfaces indicate mechanical tumbling and polishing; color may be heat-enhanced or dyed.

Identified August 19, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich fluids fill cavities and fractures, depositing microscopic quartz fibers, often in volcanic rocks; iron produces the red-orange color. Deposits commonly range from Paleozoic to Cenozoic, depending on locality.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and low-cost jewelry; polished pieces are popular mineral specimens and worry stones.

Geological facts

Carnelian is a chalcedony variety closely related to sard, which is generally darker brown-red. Its color can deepen with heating or prolonged sunlight exposure.

Field identification & locations

Common sources include India, Brazil, Uruguay, Madagascar, Botswana, and Germany. Identify by its orange-red translucency, fine texture, hardness, and lack of cleavage; glass usually shows bubbles or much lower natural variation.