Carnelian (Chalcedony)

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Orangey-red to brownish-red; Luster: Waxy to vitreous; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.58–2.64

Formation & Geological History

Formed through the deposition of silica from groundwater in cavities of igneous rocks, particularly volcanic rocks like basalt. Its color is derived from iron oxide impurities.

Uses & Applications

Predominantly used as a gemstone in jewelry (beads, cabochons), for intaglios and seals, and is highly valued by mineral collectors for its vibrant color.

Geological Facts

Carnelian has been used by humans dating back to the Neolithic era. It was highly prized in Ancient Egypt as a symbol of life and stable energy, and was often used in the cylinder seals of Mesopotamia.

Field Identification & Locations

Identify in the field by its translucent appearance and characteristic orange-red hue. It is commonly found in India, Brazil, Uruguay, and Madagascar. Look for a waxy luster and smooth surface when water-worn.

Identified on: 4/22/2026

Mode: Standard