mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White to colorless; Luster: Vitreous/glassy; Crystal Structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White to colorless
Luster: Vitreous/glassy

Identified March 4, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White to colorless; Luster: Vitreous/glassy; Crystal Structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed in cavities within volcanic or sedimentary rock layers. Groundwater rich in dissolved silica permeates gas bubbles or hollow spaces, depositing layers of crystals over millions of years. Common in Cenozoic era formations.

Uses & applications

Used primarily for display in mineral collections, home decor, educational specimens, and low-cost jewelry (metaphysical uses). Industrially, quartz is used in glassmaking and electronics.

Geological facts

Geodes are essentially 'hollow rocks' lined with crystals. They are indistinguishable from common stones on the outside, and the word 'geode' comes from the Greek word 'Geoides' meaning 'earth-like'.

Field identification & locations

Identify in the field by looking for rounded, lightweight nodules that rattle (if crystals are loose) or sound hollow when tapped. Commonly found in deserts (Sahara, Chihuahua) and regions like Iowa or Brazil. Hand-sized specimens often feature druzy or macro-crystalline centers.