mineral

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to translucent; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal (microcrystalline druzy); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to translucent
Luster: Vitreous to waxy

Identified June 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed by the precipitation of mineral-rich groundwater in cavities within sedimentary rocks or volcanic voids. These cavities fill slowly over geological time scales, ranging from thousands to millions of years.

Uses & applications

Mainly used for decorative pieces, educational specimens, gemstone collecting, and lapidary work. Quartz itself is crucial in electronics and glass manufacturing.

Geological facts

The word geode comes from the Greek word 'Geoides' meaning earth-like. No two geodes are exactly alike, and the most common mineral found lining their interior is quartz.

Field identification & locations

Identify in the field by looking for rounded, hollow nodules that feel lighter than solid rocks. When broken open, look for sparkling druzy crystals or botryoidal formations. Commonly found in limestone and volcanic ash deposits.