Carnelian Agate

Physical Properties

Hardness: 6.5-7 on Mohs scale; Color: Reddish-orange to brownish-red; Luster: Vitreous to waxy; Crystal structure: Hexagonal (trigonal) microcrystalline (Cryptocrystalline); Cleavage: None; Specific gravity: 2.58-2.64.

Formation & Geological History

Formed in low-temperature silica-rich environments, typically through the deposition of silica from groundwater in cavities of volcanic igneous rocks (geodes or veins). It gets its color from iron oxide (hematite) impurities.

Uses & Applications

Used primarily as a gemstone in jewelry (beads, cabochons, rings) and for decorative carvings, seals, and talismans.

Geological Facts

Carnelian has been used as a gemstone for over 4,500 years. Ancient Romans and Egyptians used it extensively for signet rings and amulets, believing it provided protection and courage.

Field Identification & Locations

Identify by its translucency (when held to light) and lack of distinct banding (which would make it a banded agate). Common in Brazil, India, Uruguay, and Madagascar. Collectors look for evenness of color and high translucency.

Identified on: 4/28/2026

Mode: Standard