mineral

Carnelian Agate

Carnelian (Silicon Dioxide, SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Orange, reddish-brown, or translucent peach; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline/cryptocrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64.

Hardness: 6
Color: Orange, reddish-brown, or translucent peach
Luster: Vitreous to waxy

Identified April 13, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica in groundwater within the cavities (vesicles) of volcanic rocks or sedimentary formations. Its orange color comes from iron oxide (hematite) impurities.

Uses & applications

Used primarily in jewelry making, cabochon cutting, beadwork, and decorative sculpture. Historically used for seals, talismans, and signet rings.

Geological facts

Carnelian has been used as a gemstone since the Early Neolithic. Ancient Romans and Greeks valued it for seal rings because hot wax does not stick to it.

Field identification & locations

Identify by its translucent waxy appearance and orange color. It is common in riverbeds and on beaches in volcanic regions. Notable locations include Brazil, India, Madagascar, and the Pacific Northwest of the USA.