mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Colorless to milky white crystals on a tan/yellowish matrix; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Colorless to milky white crystals on a tan/yellowish matrix
Luster: Vitreous (glassy)

Identified July 4, 2026More mineral →

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Physical properties

Formation & geological history

Formed as secondary mineral precipitates in hollow cavities (vugs) within sedimentary or volcanic rocks. Mineral-rich groundwater seeps through the porous host rock, depositing crystals over thousands of years.

Uses & applications

Commonly used for geological study, home decor, metaphysical collection, and as a source of high-purity silica for industrial applications.

Geological facts

Geodes are known as 'nature's surprise' because their unremarkable exterior hides a sparkling crystalline interior. Many quartz geodes from Morocco, like this one, date back to the Cretaceous period.

Field identification & locations

Identified by its hollow interior lined with inward-pointing crystals and a harder outer shell. They are frequently found in limestone deserts or volcanic ash beds. Look for round, lumpy rocks that feel lighter than they look.