mineral

Blue Chalcedony

Silicon Dioxide (SiO2)

Hardness: 6.5–7 on Mohs scale. Color: Pale blue, grey-blue, or lavender. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal). Cleavage: None. Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Pale blue, grey-blue, or lavender
Luster: Vitreous to waxy

Identified April 4, 2026More mineral →

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Physical properties

Hardness: 6.5–7 on Mohs scale. Color: Pale blue, grey-blue, or lavender. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal). Cleavage: None. Specific Gravity: 2.58–2.64.

Formation & geological history

Formed through the deposition of silica from water in cavities of other rocks, typically volcanic. It is a cryptocrystalline form of quartz that precipitates at relatively low temperatures.

Uses & applications

Popular in jewelry (cabochons and beads), ornamental carvings, and used by collectors and in metaphysical practices.

Geological facts

Ancient civilizations in the Mediterranean basin used blue chalcedony for seals and jewelry. It gets its distinctive color from the Tyndall effect, which is the scattering of light by microscopic inclusions.

Field identification & locations

Identify by its waxy luster, lack of cleavage, and translucent blue-grey color. It is commonly found in Turkey, Namibia, India, and the United States (specifically Oregon and Arizona).