mineral

Carnelian (Orange Chalcedony)

Silicon Dioxide (SiO2) - variety of Chalcedony

Hardness: 6.5–7 (Mohs scale); Color: Pale orange to deep reddish-brown; Luster: Waxy to vitreous; Crystal structure: Hexagonal (microcrystalline/cryptocrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64.

Hardness: 6
Color: Pale orange to deep reddish-brown
Luster: Waxy to vitreous

Identified March 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater or hydrothermal fluids in volcanic rocks, particularly within gas cavities (vesicles) of basalt or andesite. Over millions of years, the presence of iron oxide impurities creates the distinct orange-red coloration.

Uses & applications

Primarily used in jewelry making (beads, cabochons), lapidary art, and intaglio carvings. Historically used for signet rings and seals because hot wax does not stick to it.

Geological facts

Carnelian was one of the first gemstones used by humans, dating back to the Neolithic period. In ancient Egypt, it was believed to assist the deceased on their journey into the afterlife and was often featured in the jewelry of Tutankhamun.

Field identification & locations

Identify in the field by its translucent quality, waxy feel, and lack of visible crystals. It is commonly found in riverbeds, gravel pits, and coastal areas, particularly in Brazil, India, Madagascar, and the Pacific Northwest of the USA.

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