mineral

Carnelian (Orange Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Pale orange to deep reddish-brown; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal (microcrystalline/cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.64.

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

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic environments and sedimentary deposits. It typically forms from the precipitation of silica from aqueous fluids in cavities (vughs) of igneous rocks or through petrification of organic matter. Its color is derived from iron oxide impurities.

Uses & applications

Primarily used as a gemstone for jewelry (cabochons, beads, and carvings), intaglio seals, and by crystal collectors for its aesthetic appeal. Historically used as a material for seal stones in ancient civilizations.

Geological facts

Ancient Romans and Greeks used carnelian for signet rings because hot wax does not stick to it. It was also one of the stones used in the Breastplate of Aaron mentioned in the Bible. It is the modern birthstone for the zodiac sign Virgo.

Field identification & locations

Identify in the field by its semi-translucency, waxy luster, and conchoidal (shell-like) fracture. Look for it in riverbeds or gravel deposits, especially in regions with volcanic history like India, Brazil, or the Pacific Northwest (USA).

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