mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to colorless; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to colorless
Luster: Vitreous to greasy

Identified June 25, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to colorless; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed when silica-rich hydrothermal fluids or groundwater seep into cavities within igneous or sedimentary rocks, slowly precipitating crystals over thousands of years. Common in volcanic ash beds or limestone.

Uses & applications

Used in watchmaking (quartz oscillators), electronics, glass manufacturing, abrasives, and highly valued as decorative display specimens or jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Geodes are often mistaken for ordinary rocks on the exterior until they are cracked open to reveal the crystalline interior.

Field identification & locations

Identify by the presence of internal crystalline cavities and high hardness (scratches glass). Look for round or egg-shaped nodules with a bumpy outer texture in desert environments or limestone outcrops.