mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Clear to white; Luster: Vitreous/glassy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Clear to white
Luster: Vitreous/glassy

Identified May 27, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: Clear to white; Luster: Vitreous/glassy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed by the precipitation of mineral-rich water within hollow cavities of sedimentary or volcanic rocks. Over long periods, crystals grow inward from the cavity walls. They can range from millions to hundreds of millions of years in age.

Uses & applications

Primarily used for ornamental purposes, home decor, geological collecting, and educational specimens. Quartz is also used in electronics and watches for its piezoelectric properties.

Geological facts

The word 'geode' comes from the Greek word 'Geoides' meaning 'earth-like'. No two geodes are exactly alike inside, making each a unique natural time capsule.

Field identification & locations

Identify in the field by looking for rounded, hollow-feeling nodules or stones that are lighter than they appear. Often found in areas with limestone or volcanic ash deposits. A common tip for collectors is to shake the stone to see if loose crystals rattle inside.