mineral

Carnelian

Carnelian (SiO2 - Silicon Dioxide with Hematite impurities)

Hardness: 6.5-7 (Mohs scale), Color: Translucent reddish-orange to brownish-red, Luster: Vitreous to waxy, Crystal Structure: Hexagonal (trigonal) microcrystalline (cryptocrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Hardness: 6

Identified March 6, 2026More mineral →

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Physical properties

Formation & geological history

Formed in low-temperature hydrothermal environments where silica-rich fluids precipitate in the cavities of volcanic rocks (geodes) or sedimentary formations. Its color comes from iron oxide (hematite) impurities.

Uses & applications

Primarily used in jewelry (cabochons, beads, and rings), lapidary art, and ornamental carvings. It has been historically used for decorative seals and amulets.

Geological facts

In ancient Egypt, carnelian was known as 'the setting sun' and was believed to protect the wearer in the afterlife. It was widely used in ancient Roman and Greek signet rings because hot wax does not stick to its smooth surface.

Field identification & locations

Identify by its translucent reddish hue and lack of visible crystal grains. It is commonly found in India, Brazil, Uruguay, and Madagascar. Collectors should look for uniform saturation and lack of fractures; banded carnelian is occasionally referred to as sardonyx.

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