mineral

Carnelian

Silicon dioxide (SiO2) with iron oxide impurities

Hardness: 6.5–7 on the 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 February 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater into the cavities of igneous or sedimentary rocks. The orange-red color is derived from iron oxide (hematite) impurities. It can be found in volcanic rocks and as water-worn pebbles in riverbeds.

Uses & applications

Primarily used in jewelry making (beads, cabochons), lapidary art, and historical seal carving. In antiquity, it was used for signet rings and amulets.

Geological facts

Carnelian was highly prized in Ancient Egypt, where it was associated with the setting sun and the goddess Isis. It was also one of the stones used in the Breastplate of the High Priest in Biblical descriptions.

Field identification & locations

Identify by its translucent reddish-orange color and waxy luster. It lacks the banding found in typical agate. Common locations include India, Brazil, Uruguay, and Madagascar. Collectors should look for uniform color and high translucency.

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