mineral

Blue Chalcedony

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Pale blue, lavender-blue, or grey-blue. Luster: Waxy to vitreous. Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None. Specific Gravity: 2.6-2.64.

Hardness: 6
Color: Pale blue, lavender-blue, or grey-blue
Luster: Waxy to vitreous

Identified May 5, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich water in volcanic cavities or sedimentary rock fractures. It is an authigenic mineral often found in hydrothermal veins and geodes.

Uses & applications

Used primarily in lapidary work for cabochons, beads, and carvings. Also used as a healing stone in metaphysical practices and as a collector's specimen.

Geological facts

Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. The blue color is due to the Tyndall effect, which is the scattering of light by microscopic particles.

Field identification & locations

Identify in the field by its waxy luster, conchoidal fracture, and lack of visible crystals. It is frequently found in basaltic rocks or as nodules in desert environments like those in Namibia or Turkey.