mineral

Blue Chalcedony

Chalcedony (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Pale blue, lavender-blue, or gray-blue. Luster: Vitreous to waxy. Crystal Structure: Trigonally based microcrystalline quartz. Specific Gravity: 2.58-2.64.

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

Identified May 10, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Pale blue, lavender-blue, or gray-blue. Luster: Vitreous to waxy. Crystal Structure: Trigonally based microcrystalline quartz. Specific Gravity: 2.58-2.64.

Formation & geological history

Formed at low temperatures through the deposition of silica from groundwater in cavities of other rocks, particularly volcanic rocks. These often occur as botryoidal masses or lining geodes.

Uses & applications

Primarily used in jewelry for cabochons, beads, and carvings. Also used as an ornamental stone and by collectors.

Geological facts

Blue chalcedony is known for its subtle, milky translucency. Historically, it was believed to promote harmony and calm. High-quality translucent blue material from Namibia and Turkey is highly sought after.

Field identification & locations

Identify in the field by its waxy luster, lack of cleavage, conchoidal fracture, and hardness. It is commonly found in Brazil, Namibia, Turkey, and India.