Carnelian Agate

Silicon dioxide (SiO2) - variety of chalcedony

Rock Type: mineral

Carnelian Agate

Physical Properties

Hardness: 6.5-7 (Mohs scale), Color: Amber, orange to reddish-brown, Luster: Waxy to vitreous, Crystal Structure: Trigonal (cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.64

Formation & Geological History

Formed through the deposition of silica from groundwater in the cavities of igneous rocks. The orange color is caused by iron oxide impurities. These can range from modern formations to specimens millions of years old.

Uses & Applications

Primarily used in jewelry, lapidary arts for cabochons and beads, and as decorative or healing stones in alternative medicine.

Geological Facts

Carnelian was highly prized in ancient times; ancient Romans used it for signet rings and Egyptian pharaohs were often buried with it to assist in the journey to the afterlife.

Field Identification & Locations

Identify in the field by its distinctive waxy luster, translucency, and banding (which classifies it as agate). Commonly found in Brazil, India, Uruguay, and the United States (western states). Look for smooth, water-worn pebbles in riverbeds or gravel deposits.

Identified on: 5/13/2026

Mode: Standard