mineral

Quartz Geode

Crystalline Silicon Dioxide (SiO2) within a geode structure

Hardness: 7 on Mohs scale; Color: Colorless to white/milky crystals; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Colorless to white/milky crystals
Luster: Vitreous (glassy)

Identified July 1, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Colorless to white/milky crystals; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed via precipitation of mineral-rich water within cavities of volcanic or sedimentary rocks. Over long periods, silica-rich fluids deposit layers of crystals inward from the shell. Mostly from the Cenozoic era.

Uses & applications

Home decor, meditation aids, mineral collecting, education, and costume jewelry. High-quality quartz can be used for oscillating circuits in electronics.

Geological facts

Geodes appear as ordinary, round rocks from the outside. The word 'geode' comes from the Greek word 'geoides', meaning 'earth-like'. No two geodes are identical inside.

Field identification & locations

Identified in the field by their rounded, lumpy appearance and unusual lightness compared to solid rocks. Probing for hollow cavities or rattling sounds is a common collector technique. Often found in dessert regions or riverbeds.

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