mineral

Carnelian

Carnelian (SiO2 with Iron Oxide impurities)

Hardness: 6.5-7 (Mohs scale); Color: Pale orange to deep reddish-brown; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (Conchoidal fracture); Specific gravity: 2.58–2.64

Hardness: 6
Color: Pale orange to deep reddish-brown
Luster: Vitreous to waxy

Identified March 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed in low-temperature hydrothermal environments. It usually occurs as a secondary mineral in volcanic cavities or as a replacement mineral in sedimentary rocks. Its reddish-orange hue is caused by iron oxide impurities (Hematite) within the silicon dioxide structure.

Uses & applications

Primarily used in jewelry as beads or cabochons, and for carving intaglios and cameos. Historically used for making signet rings, seals, and amulets. It is also a popular specimen for crystal collecting and rock tumbling.

Geological facts

Ancient Romans used carnelian for signet rings because hot wax does not stick to the stone. It was also found in the burial chambers of Pharaohs in Ancient Egypt, where it was believed to assist the soul in its journey to the afterlife.

Field identification & locations

Identify in the field by its translucent properties when held up to light, its orange-red waxy appearance, and the lack of visible crystal grains. Common locations include Brazil, India, Uruguay, Madagascar, and parts of the United States (such as Oregon and Washington).

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