mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, clear to white or grey color, vitreous to greasy luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Identified July 30, 2026More mineral →

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Physical properties

Hardness of 7 on the Mohs scale, clear to white or grey color, vitreous to greasy luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Formation & geological history

Formed in hollow spaces in sedimentary or volcanic rocks where silica-rich groundwater or hydrothermal fluids slowly precipitate quartz crystals inward from the outer wall over millions of years.

Uses & applications

Commonly used in lapidary work, jewelry, home decor, metaphysical practices, and as collector specimens.

Geological facts

Geodes appear as ordinary, unassuming rocks on the outside, but cracking them open reveals a stunning, hollow interior lined with sparkling crystals.

Field identification & locations

Can be identified in the field by its spherical or nodular shape with a bumpy, weathered outer rind, and a significantly lighter weight than a solid rock of the same size due to the hollow interior.