mineral

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 Mohs; Color: Brownish-red, orange, or reddish-pink; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Hardness: 6
Color: Brownish-red, orange, or reddish-pink
Luster: Vitreous to waxy

Identified April 11, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Brownish-red, orange, or reddish-pink; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Formation & geological history

Formed through the deposition of silica from groundwater into cavities of igneous rocks or sedimentary formations. Its red color comes from iron oxide (hematite) impurities.

Uses & applications

Used primarily in jewelry (beads, cabochons), lapidary art, and historical seal-making (intaglios) as it does not stick to hot wax.

Geological facts

Carnelian was used by the Romans and Egyptians for signet rings and amulets. It is one of the oldest gemstones known to humans, dating back to the 4th-5th millennium BC.

Field identification & locations

Identify by its waxy luster, conchoidal fracture, and translucent clarity when held to light. Found globally in volcanic areas, notably Brazil, India, and the Pacific Northwest of the USA.