mineral

Carnelian (Red Chalcedony)

SiO2 (Silicon Dioxide) with Iron Oxide impurities

Hardness: 6.5-7 on Mohs scale. Color: Brownish-red to orange-red. Luster: Waxy to vitreous. Crystal structure: Trigonal/Microcrystalline. Cleavage: None. Fracture: Conchoidal.

Hardness: 6
Color: Brownish-red to orange-red
Luster: Waxy to vitreous

Identified June 21, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Brownish-red to orange-red. Luster: Waxy to vitreous. Crystal structure: Trigonal/Microcrystalline. Cleavage: None. Fracture: Conchoidal.

Formation & geological history

Formed via the deposition of silica from groundwater in the cavities of igneous rocks, particularly volcanic lavas. The red hue is caused by iron oxide (hematite) impurities.

Uses & applications

Extensively used in lapidary work for jewelry, cabochons, beads, and carved seals. Historically used for signet rings and amulets.

Geological facts

Carnelian was highly prized in ancient Rome and Egypt for making cylinder seals and jewelry. It is often heat-treated to darken its reddish color.

Field identification & locations

Identified in the field by its waxy luster, translucency, and shell-like (conchoidal) fracture pattern. Commonly found in riverbeds or areas with weathered volcanic rock.

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