mineral

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2)

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

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

Identified June 7, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the precipitation of silica in volcanic and sedimentary environments, often as fillings in cavities or nodules within basaltic lavas. Its orange-red color comes from iron oxide (hematite) impurities.

Uses & applications

Predominantly used as a gemstone for jewelry (cabochons, beads), decorative carvings, and pocket stones. Historically used for making signet rings and cylinder seals due to its lack of adhesion to hot wax.

Geological facts

Ancient Romans and Egyptians highly valued carnelian for its perceived healing properties and protective energies. It is the translucent variety of chalcedony that is specifically orange-red; more opaque brownish versions are called Sard.

Field identification & locations

Identify by its waxy luster and brownish-orange translucency; it will not have the concentric banding of agate. Commonly found in India, Brazil, Egypt, and Uruguay. Collectors look for uniform color and high translucency.