Mineral

Carnelian

Carnelian (Silicon Dioxide - SiO2 with Hematite impurities)

Hardness: 6.5–7 on Mohs scale; Color: Ranges from pale orange to deep reddish-brown; Luster: Vitreous to waxy; Crystal structure: Hexagonal (trigonal) cryptocrystalline chalcedony; Cleavage: None; Specific gravity: 2.58–2.64.

Hardness: 6
Color: Ranges from pale orange to deep reddish-brown
Luster: Vitreous to waxy

Identified March 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater or thermal fluids into gas pockets (vesicles) of volcanic rocks. The reddish color is caused by iron oxide (iron impurities) becoming oxidized. It occurs in volcanic environments and sedimentary deposits globally.

Uses & applications

Predominantly used as a gemstone for jewelry (necklaces, rings, beads), seals, cabochons, and ornamental carvings. Historically used for signet rings and cameos due to its wax-shedding properties.

Geological facts

In ancient times, Egyptians called carnelian 'the setting sun' and used it as a symbol of life and vitality. It was widely used by Roman and Greek craftsmen for intaglio gems. Its color can often be enhanced or changed through natural or artificial heat treatment.

Field identification & locations

Identify in the field by its waxy luster, conchoidal (shell-like) fracture, and translucent to semi-opaque orange-red appearance. Commonly found in Brazil, India, Uruguay, Madagascar, and the US (Oregon/Washington). Collectors look for uniform color and high translucency.

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