mineral

Carnelian (Chalcedony)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

AI-generated identification · may be incorrect

Hardness: 6.5 - 7 on Mohs scale; Color: Orange, reddish-brown, yellow-orange; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None, exhibits conchoidal fracture; Specific Gravity: 2.58 - 2.64.

Hardness: 6
Color: Orange, reddish-brown, yellow-orange
Luster: Vitreous to waxy

Identified July 22, 2026More mineral →

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Physical properties

Formation & geological history

Forms in low-temperature hydrothermal environments, volcanic rocks, and gas cavities (geodes) when silica-rich fluids deposit in rock crevices, gaining its reddish-orange tone from iron oxide impurities.

Uses & applications

Used widely in jewelry (beads, cabochons, carved rings), lapidary art, and as a popular collectible gemstone.

Geological facts

Carnelian has been used for ornamentation for over 4,500 years. Ancient Romans used carnelian signet rings to seal official documents because hot wax does not stick to it.

Field identification & locations

Look for a translucent to semi-translucent reddish-orange color with a characteristic waxy surface texture and smooth conchoidal fractures. Commonly found in India, Brazil, Madagascar, and parts of the USA.