mineral

Blue Chalcedony

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Grayish-blue, lavender-blue; Luster: Vitreous to waxy; Structure: Cryptocrystalline (hexagonal/trigonal); Specific Gravity: 2.6-2.64.

Hardness: 6
Color: Grayish-blue, lavender-blue
Luster: Vitreous to waxy

Identified July 9, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Grayish-blue, lavender-blue; Luster: Vitreous to waxy; Structure: Cryptocrystalline (hexagonal/trigonal); Specific Gravity: 2.6-2.64.

Formation & geological history

Formed through the deposition of silica from aqueous solutions at relatively low temperatures in volcanic cavities, sedimentary rocks, and hydrothermal veins. Often found in nodules or geodes.

Uses & applications

Primarily used as a gemstone for jewelry (cabochons, beads), decorative carvings, and in metaphysical stone collecting. Historically used for seals and cameos.

Geological facts

Chalcedony is named after the ancient Byzantine port city of Chalcedon. It is a fibrous variety of quartz where crystals are too small to be seen under a standard microscope.

Field identification & locations

Identify by its translucent waxy appearance, conchoidal fracture, and lack of visible crystal faces. Common locations include Namibia, Turkey, India, and the United States (Oregon and California).