mineral

Carnelian Agate

Silicon Dioxide (SiO2) with iron oxide impurities

Hardness: 6.5-7.0 (Mohs); Color: Pale orange to deep reddish-brown; Luster: Waxy to vitreous; Crystal Structure: Trigonal (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 May 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a secondary mineral in volcanic rock cavities or sedimentary environments through the deposition of silica-rich ground water. Most frequently found in weathered volcanic rocks such as basalt.

Uses & applications

Used primarily in jewelry (cabochons, beads, carved seals), decorative carvings, and as a semi-precious collector's gemstone.

Geological facts

Ancient Romans used carnelian for signet rings because hot wax does not stick to the stone. Many ancient Egyptian burial artifacts featured carnelian as it was believed to assist the soul in its journey to the afterlife.

Field identification & locations

Identify in the field by its translucency, waxy luster, and reddish-orange banding or mottling. Commonly found in Brazil, India, Uruguay, and Madagascar.

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