Mineral

Carnelian (a variety of Chalcedony)

Silicon Dioxide (SiO₂)

Hardness: 6.5–7 on the Mohs scale. Color: Orangish-red to translucent brownish-orange. Luster: Vitreous to waxy. Crystal structure: Cryptocrystalline (Trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

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

Identified March 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica by groundwater in volcanic and sedimentary rocks. Its reddish hue comes from iron oxide impurities (hematite). It can be found in a variety of geological ages, particularly within ancient basalt cavities.

Uses & applications

Predominantly used as a gemstone in jewelry, beads, seals, and lapidary art. Historically used for signet rings and amulets due to its toughness and ability to not stick to hot wax.

Geological facts

In Ancient Egypt, carnelian was believed to have protective properties for the deceased. It was one of the stones used in the Breastplate of Aaron. Much modern carnelian is actually lower-quality chalcedony that has been heat-treated or dyed to enhance its color.

Field identification & locations

Identify in the field by its translucency, waxy luster, and lack of visible grains. Common locations include Brazil, India, Uruguay, Madagascar, and the United States (Oregon/Washington). Collectors look for uniform color and high translucency.

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