mineral

Carnelian Agate

Carnelian (Silicon Dioxide, SiO2)

Hardness: 6.5-7 Mohs; Color: Brownish-red to orange; Luster: Vitreous to waxy; Crystal Structure: Trigonal (cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Brownish-red to orange
Luster: Vitreous to waxy

Identified July 1, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Brownish-red to orange; Luster: Vitreous to waxy; Crystal Structure: Trigonal (cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.64.

Formation & geological history

Formed through the deposition of silica in cavities of volcanic rocks or sedimentary formations. Its orange color comes from iron oxide impurities (hematite). It can be found in formations ranging from the Cenozoic to prehistoric eras.

Uses & applications

Used primarily in jewelry (beads, cabochons), carvings, seal stones, and as a collector's specimen. In industry, chalcedony is sometimes used for its hardness in specialized precision tools.

Geological facts

Ancient Egyptians called carnelian 'the setting sun' and used it in amulets for protection. It has been used for making cylinder seals and signet rings for thousands of years because hot wax does not stick to it.

Field identification & locations

Identify in the field by its waxy luster, conchoidal fracture (smooth, curved breaks), and translucent orange-red hue. Commonly found in Brazil, India, Uruguay, and parts of the United States like Oregon.