mineral

Carnelian

Silicon dioxide (SiO2) - variety of Chalcedony

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Orange, reddish-brown, or brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Orange, reddish-brown, or brownish-red
Luster: Vitreous to waxy

Identified June 29, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Orange, reddish-brown, or brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Forms in volcanic rocks where silica-rich groundwater percolates through cavities, depositing layers of microcrystalline quartz. Red color is due to iron oxide impurities.

Uses & applications

Primarily used in jewelry (cabochons and beads), decorative carvings, and seal stones. Historically used for signet rings.

Geological facts

In ancient times, carnelian was believed to protect against evil spirits and was found in ancient Egyptian tombs. It was also used in Roman signet rings because hot wax does not stick to it.

Field identification & locations

Identify by its translucent, waxy appearance and warm reddish-orange hue. It lacks the banding seen in Agate. It is commonly found in India, Brazil, Uruguay, and Madagascar.