Blue Chalcedony

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Light blue to lavender-blue; Luster: Vitreous to waxy; Crystal structure: Trigonal/Monoclinic (microscopic); Cleavage: None; Specific Gravity: 2.58-2.64

Formation & Geological History

Formed through the deposition of silica-rich water in cavities of volcanic igneous rocks or sedimentary environments. It develops at low temperatures over millions of years as microcrystalline fibers.

Uses & Applications

Commonly used in jewelry (cabochons, beads), decorative carvings, and as a healing stone in metaphysical practices. It is also a popular collector's specimen.

Geological Facts

Blue Chalcedony is often translucent. The 'blue' color is typically the result of the Tyndall effect—the scattering of light by microscopic particles—rather than a specific chemical pigment.

Field Identification & Locations

Identify in the field by its waxy luster, conchoidal (shell-like) fracture patterns, and lack of visible crystal faces. Note its hardness prevents it from being scratched by a steel knife. Common locations include Namibia, Turkey, Malawi, and the USA (Oregon/California).

Identified on: 4/20/2026

Mode: Standard