Chalcedony (Agate/Carnelian variant)

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Translucent tan to honey-yellow; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline (Trigonal/Monoclinic); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58–2.64

Formation & Geological History

Formed from the deposition of silica-rich water in cavities of volcanic or sedimentary rocks. This specific piece appears water-worn, suggesting it was found in a riverbed or alluvial deposit.

Uses & Applications

Commonly used for lapidary work, decorative carvings, jewelry beads, and as a popular focus for rockhounding collectors.

Geological Facts

Chalcedony is a broad term for all cryptocrystalline quartz. When it exhibits banding, it is called Agate; when it is reddish-brown, it is Carnelian. This translucent honey-colored variety is often found in river gravels globally.

Field Identification & Locations

Identify in the field by its waxy texture, inability to be scratched by a steel knife, and smooth, curved (conchoidal) fracture surfaces. Commonly found in riverbeds, beaches, and desert washes.

Identified on: 4/25/2026

Mode: Standard