Carnelian

Physical Properties

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

Formation & Geological History

Formed through the deposition of silica from groundwater into cavities of igneous rocks, particularly volcanic lavas. The reddish-orange color comes from iron oxide (hematite) impurities and is often enhanced by natural solar heat or volcanic activity over millions of years.

Uses & Applications

Predominantly used as a gemstone for jewelry, lapidary carvings, seals, and as a popular collector's mineral. Historically used for signet rings and amulets due to its durability.

Geological Facts

In Ancient Egypt, carnelian was known as 'the setting sun' and was associated with the blood of Isis. It was one of the first stones used in bead-making in the Neolithic period and is a variety of chalcedony.

Field Identification & Locations

Identify in the field by its translucency, waxy luster, and uniform orange-to-red color without the banding typical of agate. Often found in riverbeds or volcanic regions like India, Brazil, and Uruguay.

Identified on: 4/13/2026

Mode: Standard