mineral

Carnelian

Carnelian (Silicon Dioxide - SiO2)

Hardness: 6.5–7 on the Mohs scale; Color: Reddish-orange, brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64

Hardness: 6
Color: Reddish-orange, brownish-red
Luster: Vitreous to waxy

Identified April 2, 2026More mineral →

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Physical properties

Hardness: 6.5–7 on the Mohs scale; Color: Reddish-orange, brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64

Formation & geological history

Formed in low-temperature hydrothermal environments, often filling cavities in volcanic rocks (geodes or veins). It gains its color from iron oxide (hematite) impurities and can be found in sedimentary deposits after erosion of the host rock.

Uses & applications

Used primarily as a semi-precious gemstone in jewelry (beads, cabochons), carvings, signet rings (intaglios), and as a collector's specimen.

Geological facts

Carnelian has been used by humans for over 4,500 years. The ancient Egyptians called it the 'setting sun' and used it in amulets to protect the dead in the afterlife; it was also used in Roman seals because hot wax does not stick to it.

Field identification & locations

Identify in the field by its distinctive translucency and reddish-orange hue. It is commonly found in Brazil, India, Uruguay, and Madagascar. Most commercial carnelian is actually dyed chalcedony; natural carnelian often shows a cloudy distribution of color.