mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: Clear to white, sometimes with yellowish or brownish iron oxide staining. Luster: Vitreous (glassy) to dull on the outer matrix. Crystal Structure: Trigonal. Cleavage: None (exhibits conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale
Luster: Vitreous (glassy) to dull on the outer matrix

Identified August 1, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hollow cavities in rocks, most commonly in sedimentary or volcanic environments, through the slow precipitation of silica-rich groundwater over millions of years.

Uses & applications

Used in mineral collecting, decorative display pieces, jewelry making, and metaphysical practices.

Geological facts

Quartz is one of the most abundant minerals in Earth's continental crust. Geodes form when mineral-rich water seeps into a hollow cavity inside a rock, such as an animal burrow, tree root, or gas bubble in volcanic lava, slowly forming interlocking quartz crystals lining the inside.

Field identification & locations

Easily identified by its distinctive crystal points lining a cavity, high hardness capable of scratching glass, and lack of cleavage. Commonly found worldwide, with notable deposits in Brazil, Mexico, Uruguay, and the United States (such as in Kentucky, Indiana, and Iowa).