mineral

Carnelian (a variety of Chalcedony)

SiO2 (Silicon Dioxide) primarily colored by iron oxide (Hematite)

Hardness: 6.5-7 (Mohs scale); Color: Orange-red to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64

Hardness: 6
Color: Orange-red to brownish-red
Luster: Vitreous to waxy

Identified March 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed in low-temperature hydrothermal environments where silica-rich fluids precipitate in cavities of volcanic rocks (basalt/andesite) or sedimentary environments. It can form in any geological era, often found in weathered volcanic soils.

Uses & applications

Primarily used in jewelry making (beads, cabochons), carvings, decorative seals, and as a popular specimen for gemstone collectors.

Geological facts

Carnelian was highly prized in ancient times; it was used by the Egyptians in burial rites and by the Romans to make signet rings because hot wax does not stick to it. It has been used in jewelry for over 4,500 years.

Field identification & locations

Identify in the field by its translucent orange-red hue and smooth, waxy feel. It is commonly found in India, Brazil, Uruguay, and the United States (Washington, Oregon). Collectors should look for uniform color and high translucency.

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