Mineral

Carnelian Agate

Carnelian (Silicon Dioxide - SiO2 with Iron Oxide impurities)

Hardness: 6.5-7 (Mohs scale); Color: Reddish-brown, orange, brownish-red; Luster: Waxy to vitreous; Crystal structure: Trigonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Reddish-brown, orange, brownish-red
Luster: Waxy to vitreous

Identified April 11, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Reddish-brown, orange, brownish-red; Luster: Waxy to vitreous; Crystal structure: Trigonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & geological history

Formed through the deposition of silica from groundwater in the cavities of igneous rocks. The reddish color is due to iron oxide (hematite) impurities and often intensifies after exposure to heat or sunlight.

Uses & applications

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

Geological facts

Carnelian has been used as a gemstone since the Early Neolithic. Ancient Romans used it for signet rings because hot wax does not stick to it. It was also highly valued in ancient Egypt as a symbol of life and vitality.

Field identification & locations

Identify by its waxy luster, translucency when held to light, and lack of visible crystalline texture. Commonly found in riverbeds or beaches where agatized material has weathered out of basalt. Notable locations include India, Brazil, Uruguay, and Madagascar.

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