Carnelian (Orange Agate/Chalcedony)

Physical Properties

Hardness: 6.5-7 on Mohs scale; Color: Orange to reddish-brown; Luster: Waxy to vitreous; Crystal Structure: Hexagonal (trigonal) microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64

Formation & Geological History

Formed through the deposition of silica from groundwater in the cavities of igneous rocks, particularly volcanic lavas. The orange color comes from iron oxide (hematite) impurities.

Uses & Applications

Used primarily as a semi-precious gemstone in jewelry (beads, cabochons), carved seals, and as decorative pocket stones for collectors.

Geological Facts

Carnelian was widely used in ancient Rome for signet rings and seals because hot wax does not stick to it. It has been used for jewelry since the Neolithic period.

Field Identification & Locations

Identify in the field by its waxy luster, conchoidal (shell-like) fracture, and translucent orange hue. Often found in riverbeds or on beaches in volcanic regions.

Identified on: 4/22/2026

Mode: Standard