mineral

Quartz Geode

Crystalline Quartz (SiO2) within a sedimentary/igneous host

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: Clear to white crystals in a grey/brown rind, Luster: Vitreous (glassy) crystals, Crystal structure: Trigonal/Hexagonal, Specific Gravity: 2.65

Identified July 20, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Clear to white crystals in a grey/brown rind, Luster: Vitreous (glassy) crystals, Crystal structure: Trigonal/Hexagonal, Specific Gravity: 2.65

Formation & geological history

Formed when gas bubbles in volcanic rock or cavities in sedimentary rock are filled by hydrothermal fluids over thousands of years, allowing quartz crystals to grow inward from the hollow center.

Uses & applications

Primarily used for home decor, educational displays, geological collecting, and metaphysical purposes.

Geological facts

The name 'geode' comes from the Greek word 'Geoides' meaning 'earth-like'. No two geodes are exactly alike, and they often look like ordinary, bumpy rocks until they are cracked open.

Field identification & locations

Identified in the field by their rounded or potato-like shape and unusually light weight for their size. Prolific sources include Brazil, Mexico, and the Midwestern United States (Keokuk region).