Chalcedony (Carnelian/Agate variety)

Physical Properties

Hardness: 6.5-7 Mohs; Color: Orange, reddish-brown, yellow; Luster: Waxy to vitreous; Crystal structure: Trigonal/Monoclinic (Cryptocrystalline); Cleavage: None; Specific gravity: 2.58-2.64

Formation & Geological History

Found in hydrothermal environments, volcanic cavities, and as water-worn pebbles in sedimentary deposits. Formed via slow precipitation of silica. Age varies widely by deposit location.

Uses & Applications

Used primarily in jewelry (beads, cabochons), lapidary art, seal stones, and as metaphysical pocket stones. Historically used for intaglios and cameos.

Geological Facts

Carnelian was used by ancient Egyptians as a stone of vitality and protection. The name likely comes from the Latin 'cornum' meaning cornel cherry due to its color.

Field Identification & Locations

Identify in the field by its waxy luster, conchoidal fracture, and translucency when held to light. Often found in riverbeds or beaches as rounded, smooth nodules.

Identified on: 4/21/2026

Mode: Standard