mineral

Blue Chalcedony

Microcrystalline Quartz (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Pale blue, lavender-blue, or translucent gray-blue; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64

Hardness: 6
Color: Pale blue, lavender-blue, or translucent gray-blue
Luster: Waxy to vitreous

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from hydrothermal fluids or groundwater in cavities of igneous or sedimentary rocks. It often occurs as botryoidal masses or veins and can be found in formations ranging from recent to millions of years old.

Uses & applications

Primarily used in the jewelry industry for cabochons and beads, as well as in lapidary arts for carvings and ornamental objects. It is also a popular specimen for rock and mineral collectors.

Geological facts

Blue Chalcedony is often called the 'Speaker's Stone' in metaphysical circles. Historically, it was used in ancient Rome and Greece for seals, signet rings, and cameos because it does not stick to hot wax.

Field identification & locations

Identify in the field by its waxy luster, conchoidal fracture, and lack of visible crystals. It is commonly found in basalt cavities, desert regions, and riverbeds. Key locations include Namibia, Turkey, Malawi, and the United States (Oregon/California).