mineral

Blue Chalcedony

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Pale blue, lavender-blue, or teal; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.60-2.65.

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

Identified June 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities and cracks of volcanic rocks or sedimentary environments through the deposition of silica-rich fluids at relatively low temperatures. Associated with basaltic or rhyolitic host rocks.

Uses & applications

Primarily used in jewelry for cabochons and beads, as well as for decorative carvings, seals, and as an ornamental gemstone.

Geological facts

Historical records show blue chalcedony was used by the ancient Babylonians and Romans for seal stones and rings. The name likely originates from the ancient Greek town of Chalkedon.

Field identification & locations

Identify by its waxy luster, lack of visible crystals, and translucent to opaque appearance. It is commonly found in Turkey, Namibia, Brazil, and the Southwestern United States.