Carnelian

Physical Properties

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

Formation & Geological History

Formed through the accumulation of silica in volcanic and sedimentary rocks. The orange color comes from iron oxide (hematite) impurities. It often forms as geode fillings or nodules in ancient volcanic cavities.

Uses & Applications

Used primarily for jewelry (beads, cabochons), ornamental carvings, and seal stones. Historically used for signet rings and intaglios due to its wax-shedding properties.

Geological Facts

Carnelian was highly prized by the ancient Romans and Egyptians, who associated it with the setting sun and fertility. It was often placed inside tombs to assist the soul's journey to the afterlife.

Field Identification & Locations

Identify by its translucent brownish-orange hue and waxy surface. In the field, look for smooth, ocean- or river-tumbled pebbles with a internal 'glow' when held to light. Common in Brazil, India, and Uruguay.

Identified on: 4/22/2026

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