mineral

Carnelian

SiO2 (Microcrystalline Quartz / Chalcedony)

Hardness: 6.5-7 on Mohs scale; Color: Reddish-orange, orange, to brownish-red with subtle banding; Luster: Vitreous to waxy (when tumbled/polished); Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Reddish-orange, orange, to brownish-red with subtle banding
Luster: Vitreous to waxy (when tumbled/polished)

Identified July 25, 2026More mineral →

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Physical properties

Formation & geological history

Forms at low temperatures through the deposition of silica-rich fluid within cavities and fractures of volcanic rocks. The distinct red-orange hue is caused by iron oxide impurities (goethite or hematite).

Uses & applications

Used extensively as a gemstone in jewelry, beads, polished cabochons, carvings, seal rings, and crystal collections.

Geological facts

Carnelian was widely used in ancient civilizations, including Egypt, Rome, and Greece. Ancient Romans used carnelian signet rings to seal wax documents because hot wax does not stick to it.

Field identification & locations

Identified by its warm translucent reddish-orange color, microcrystalline structure, and smooth waxy finish when polished. Common in India, Brazil, Madagascar, Uruguay, and Oregon, USA.

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Mineral/Rock