mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs), Color: Clear/white crystals within a tan/brown matrix, Luster: Vitreous (glassy) crystals, Crystal structure: Hexagonal/Trigonal, Specific Gravity: 2.65

Identified June 22, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs), Color: Clear/white crystals within a tan/brown matrix, Luster: Vitreous (glassy) crystals, Crystal structure: Hexagonal/Trigonal, Specific Gravity: 2.65

Formation & geological history

Formed in hollow cavities of sedimentary or volcanic rocks. Mineral-rich water seeps through the shell, depositing crystals on the interior walls over thousands to millions of years.

Uses & applications

Primarily used for decorative purposes, educational displays, jewelry (when sliced), and as metaphysical/collectible specimens.

Geological facts

The word geode comes from the Greek word 'Geoides' which means earth-like. No two geodes are exactly alike on the inside, and they can range from the size of a pea to massive cathedral geodes several feet tall.

Field identification & locations

Identify in the field by looking for round or egg-shaped nodules with a bumpy outer texture that feel unusually light for their size. Common locations include Brazil, Mexico, and the United States (specifically Utah and Iowa).