Carnelian Agate

Physical Properties

Hardness: 6.5–7 on Mohs scale. Color: Translucent reddish-brown, orange, or flesh-color. Luster: Waxy to vitreous. Crystal structure: Hexagonal (trigonal) microcrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

Formation & Geological History

Formed in volcanic and sedimentary rocks when silica-rich groundwater fills gas cavities (vesicles) or cracks. The red color is caused by iron oxide impurities. It occurs in various geological ages ranging from ancient Precambrian to more recent volcanic deposits.

Uses & Applications

Used primarily in lapidary arts for jewelry, beads, cabochons, and ornamental carvings. Historically used for signet rings and seals because hot wax does not stick to it.

Geological Facts

Carnelian was highly prized in ancient Egypt, where it was thought to provide protection in the afterlife. It was also used by the Romans and Greeks for decorative jewelry and intaglios. The name comes from the Latin 'carne' meaning flesh.

Field Identification & Locations

Identify in the field by its translucent quality under a light source, waxy texture, and conchoidal (shell-like) fracture pattern. Commonly found in riverbeds or beaches in regions such as India, Brazil, and the Pacific Northwest (USA).

Identified on: 4/16/2026

Mode: Standard