mineral

Blue Chalcedony

Chalcedony (cryptocrystalline Silicon Dioxide - SiO2)

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

Hardness: 6
Color: Waxy blue, lavender, or light grey
Luster: Vitreous to waxy

Identified March 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich water in volcanic cavities (vesicles) or sedimentary environments. It can form at low temperatures in mineral veins or as a chemical precipitate in nodules.

Uses & applications

Commonly used in jewelry (cabochons and beads), ornamental carvings, stone seals, and for metaphysical purposes in the crystal healing community.

Geological facts

Chalcedony was prized in the ancient world; it was used for seal rings in ancient Rome and Greece. Its name is derived from the ancient Greek town of Chalcedon in Asia Minor.

Field identification & locations

Identify in the field by its waxy luster, smooth conchoidal (shell-like) fracture, and translucent edges. It is often found in basaltic rocks or as river pebbles. Key locations include Namibia, Turkey, India, and the United States (Oregon and California).

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