mineral

Carnelian

Carnelian (SiO2 with iron oxide impurities)

Hardness: 6.5-7 on Mohs scale; Color: Reddish-orange to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Cryptocrystalline; Specific Gravity: 2.59-2.61. This specimen is polished and translucent.

Hardness: 6
Color: Reddish-orange to brownish-red
Luster: Vitreous to waxy

Identified July 1, 2026More mineral →

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Physical properties

Formation & geological history

Formed by the precipitation of silica from groundwater into cavities of igneous rocks, particularly volcanic lavas. The reddish color is due to iron oxide (hematite) impurities and can be enhanced by heat treatment.

Uses & applications

Widely used for centuries in jewelry, beadwork, seals, cabochons, and as a decorative collector's stone. In ancient times, it was popular for signet rings and amulets.

Geological facts

Ancient Egyptians called carnelian 'the setting sun' or 'the blood of Isis.' It was believed to provide courage and protection in the afterlife. It is the red variety of Chalcedony.

Field identification & locations

Identified by its waxy luster, lack of visible crystals (cryptocrystalline), and its distinct orange-red translucency. Commonly found in Brazil, India, Uruguay, Madagascar, and the United States.

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