mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, color ranges from clear to white or grey with crystalline interiors, vitreous luster, hexagonal crystal system, no cleavage, specific gravity of 2.65.

Identified August 6, 2026More mineral →

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Physical properties

Hardness of 7 on the Mohs scale, color ranges from clear to white or grey with crystalline interiors, vitreous luster, hexagonal crystal system, no cleavage, specific gravity of 2.65.

Formation & geological history

Formed in hollow cavities in sedimentary or volcanic rocks where silica-rich groundwater percolates and slowly precipitates quartz crystals over thousands to millions of years.

Uses & applications

Used in crystal collecting, decorative display pieces, and occasionally lapidary arts.

Geological facts

Geodes appear as ordinary, unassuming rocks on the outside, but cracking them open reveals a stunning, sparkling interior of crystal formations.

Field identification & locations

Can be identified in the field by their roughly spherical or nodular shape, bumpy weathered exterior, and a hollow sound or lighter weight compared to solid rocks of similar size.