mineral

Carnelian

Carnelian Chalcedony (SiO2)

Hardness: 6.5-7.0 (Mohs scale); Color: Reddish-brown to orange; Luster: Vitreous to waxy; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific gravity: 2.58–2.64.

Hardness: 6
Color: Reddish-brown to orange
Luster: Vitreous to waxy

Identified April 11, 2026More mineral →

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Physical properties

Hardness: 6.5-7.0 (Mohs scale); Color: Reddish-brown to orange; Luster: Vitreous to waxy; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific gravity: 2.58–2.64.

Formation & geological history

Formed in volcanic cavities or sedimentary environments where silica-rich groundwater precipitates. The orange-red color is caused by iron oxide (hematite) impurities. It can be found in formations ranging from recent to millions of years old.

Uses & applications

Used primarily in lapidary arts for jewelry, beads, cabochons, and decorative carvings. Historically important for seal stones and intaglios.

Geological facts

Carnelian was used by ancient Romans to make seal rings for imprinting wax because hot wax does not stick to it. It has been a sacred stone in many cultures, including Ancient Egypt where it was known as 'The Setting Sun'.

Field identification & locations

Identify in the field by its translucent body, smooth waxy fracture, and vibrant orange-red hue. Commonly found in riverbeds or coastal areas in Brazil, India, Uruguay, and the United States (especially the Pacific Northwest).