mineral

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in a Geodic Concretion

AI-generated identification · may be incorrect

Hardness: 7.0 Mohs; Color: White to colorless; Luster: Vitreous/glassy; Structure: Hexagonal crystals; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7
Color: White to colorless
Luster: Vitreous/glassy

Identified July 10, 2026More mineral →

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Physical properties

Hardness: 7.0 Mohs; Color: White to colorless; Luster: Vitreous/glassy; Structure: Hexagonal crystals; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed in cavites of sedimentary or volcanic rock. Groundwater containing dissolved minerals seeps into hollow spaces, cooling or evaporating to precipitate crystal layers over thousands to millions of years. Commonly associated with Cretaceous or Mississippian periods.

Uses & applications

Home decor, education/science kits, lapidary art, metaphysical collecting, and small jewelry accents.

Geological facts

The word 'geode' comes from the Greek word 'Geoides' meaning earth-like. Unlike a vug, which is a cavity in rock, a geode is a separable, discrete structure.

Field identification & locations

Identified by a round or egg-shaped exterior with a bumpy or 'cauliflower' texture. They feel lighter than solid rocks of similar size due to the hollow interior. Commonly found in deserts (Sahara) and riverbeds in the Midwestern USA.