Carnelian (Chalcedony)

Physical Properties

Hardness: 6.5-7 on Mohs scale; Color: Reddish-orange to brownish-red; 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 in the cavities of igneous rocks, particularly volcanic lavas. The reddish hue is caused by iron oxide (hematite) impurities.

Uses & Applications

Primarily used as a gemstone for jewelry (cabochons, beads, rings), carvings, seals, and as a popular specimen for crystal collectors.

Geological Facts

In ancient times, carnelian was believed to give courage in battle and help speakers become eloquent. It was widely used in ancient Rome and Egypt for signet rings and amulets.

Field Identification & Locations

Identified by its waxy luster, translucency, and warm orange-red color. It lacks the distinct banding of agate. Found commonly in Brazil, India, Uruguay, and Madagascar.

Identified on: 5/17/2026

Mode: Standard