mineral

Blue Chalcedony

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Light periwinkle blue to grayish-blue; Luster: Waxy to vitreous; Crystal structure: Trigonal (microcrystalline/cryptocrystalline quartz); Cleavage: None; Specific gravity: 2.58-2.64.

Hardness: 6
Color: Light periwinkle blue to grayish-blue
Luster: Waxy to vitreous

Identified July 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich hydrothermal fluids in cavities, veins, and fractures within volcanic and sedimentary rocks at relatively low temperatures.

Uses & applications

Carved into gemstone points, beads, and cabochons for jewelry, ornamental objects, and crystal healing collections.

Geological facts

Chalcedony is a cryptocrystalline form of silica composed of very fine intergrowths of quartz and moganite. Blue chalcedony often exhibits a gentle translucency that gives it a distinctive soft glow under light.

Field identification & locations

Commonly sourced from Namibia, Turkey, India, Madagascar, and the United States. Field identification features its microcrystalline waxy texture, lack of cleavage, smooth conchoidal fracture, and light blue hue.