Carnelian

Physical Properties

Hardness: 6.5-7 (Mohs). Color: Orange, reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal) microcrystalline. Cleavage: None. Specific Gravity: 2.58-2.64.

Formation & Geological History

Forms through the precipitation of silica from groundwater within cavities of volcanic or sedimentary rocks, often enriched with iron oxide impurities which provide the color. Commonly found in ancient riverbeds and volcanic deposits.

Uses & Applications

Extensively used in lapidary work for cabochons, beads, intaglios, and engraved signet rings. High historical significance in jewelry and talismans.

Geological Facts

Carnelian was deeply valued in Ancient Egypt and Mesopotamia; it was used for the seal of the Prophet Muhammad and is associated with courage in various folklore traditions.

Field Identification & Locations

Identify in the field by its translucent orange-red hue, waxy luster when tumbled, and conchoidal fracture. Common locations include Brazil, India, Uruguay, and Madagascar.

Identified on: 5/13/2026

Mode: Standard