mineral

Carnelian

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Reddish-orange to brownish-red, Luster: Vitreous to waxy, Crystal Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.59-2.61

Hardness: 6

Identified May 24, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Reddish-orange to brownish-red, Luster: Vitreous to waxy, Crystal Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.59-2.61

Formation & geological history

Formed through the deposition of silica from groundwater in the cavities of igneous rocks such as basalt. The reddish hue comes from iron oxide impurities (hematite).

Uses & applications

Primarily used as a gemstone for jewelry (beads, cabochons), carvings, decorative ornaments, and for lapidary rough.

Geological facts

Carnelian has been used as a gemstone since the Neolithic period and was highly prized by the ancient Romans and Egyptians for signet rings and amulets.

Field identification & locations

Identify by its translucent, waxy appearance and orange-red hue. It is commonly found in India, Brazil, Uruguay, and Madagascar. In the field, look for nodules with a weathered exterior and a colorful, waxy interior when fractured.