mineral

Blue Chalcedony

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Pale blue to lavender-grey. Luster: Waxy to vitreous. Crystal structure: Trigonal (microcrystalline/fibrous). Specific gravity: 2.58-2.64. Diaphaneity: Translucent to opaque.

Hardness: 6
Color: Pale blue to lavender-grey
Luster: Waxy to vitreous

Identified June 7, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed via low-temperature precipitation from silica-rich groundwater in cavities of various rock types, commonly volcanic (basalt) or sedimentary. Its age ranges from millions of years to relatively modern deposits depending on the locality.

Uses & applications

Extensively used in jewelry (cabochons, beads, carvings), ornamental objects, and as a popular specimen for crystal healing collectors. Also used as seal stones historically.

Geological facts

The name 'Chalcedony' is derived from the ancient Greek town of Chalkedon in Asia Minor. It is actually a microcrystalline variety of quartz, meaning its crystals are too small to be seen without high magnification.

Field identification & locations

Identify by its waxy luster, lack of cleavage, conchoidal fracture, and distinct blue-grey translucency. Commonly found in Namibia, Turkey, India, and the United States (California/Oregon).