mineral

Carnelian

SiO2 (Silicon Dioxide) - Translucent reddish-brown variety of Chalcedony

Hardness: 6.5–7 on the Mohs scale. Color: Orange to reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal) microcrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.59–2.61.

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

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater into cavities of igneous rocks, such as basalt or rhyolite. The distinct red-orange color is caused by impurities of iron oxide (hematite) during formation.

Uses & applications

Predominantly used as a gemstone in jewelry, including rings, beads, and cabochons. It is also used for carving seals, intaglios, and small ornamental objects. In antiquity, it was popular for signet rings.

Geological facts

Carnelian has been used for over 4,500 years; ancient Egyptians referred to it as 'the setting sun' and buried carnelian amulets with the dead to assist in the journey to the afterlife. It was also widely used in Roman 'intaglio' seal rings because hot wax does not stick to it.

Field identification & locations

Identify in the field by its translucency (light can pass through), waxy luster, and lack of visible crystalline structure (cryptocrystalline). It is commonly found in India, Brazil, Uruguay, and Madagascar. Collectors look for stones with a uniform, deep reddish-orange hue without cracks.

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