mineral

Blue Chalcedony

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Light blue to grayish-blue; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.6

Hardness: 6
Color: Light blue to grayish-blue
Luster: Waxy to vitreous

Identified July 18, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Light blue to grayish-blue; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.6

Formation & geological history

Formed via the deposition of silica-rich water in cavities (vugs) within volcanic rocks or sedimentary environments. Most specimens are from the Tertiary period or older.

Uses & applications

Used primarily in jewelry as cabochons, for ornamental carvings, and as a healing stone in metaphysical communities.

Geological facts

Chalcedony was once thought to possess the power to banish phantoms and visions of the night. It is the birthstone for the zodiac sign Cancer.

Field identification & locations

Identified by its waxy luster, conchoidal fracture, and lack of visible crystals. Commonly found in Namibia, Turkey, India, and the United States (Oregon/California).