mineral

Quartz Geode (Cracked)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Brownish outer rind with clear to white crystalline interior; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Specific gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: Brownish outer rind with clear to white crystalline interior
Luster: Vitreous to waxy

Identified April 6, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Brownish outer rind with clear to white crystalline interior; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Specific gravity: 2.65.

Formation & geological history

Formed by mineral precipitation from hydrothermal fluids or groundwater within cavities of volcanic or sedimentary rocks over thousands to millions of years.

Uses & applications

Commonly used for geological education, home decor, metaphysical collecting, and as a source for quartz in minor industrial applications.

Geological facts

Geodes are often referred to as 'thunder eggs' when they are solid or have specific volcanic origins. Though they look like plain rocks on the outside, their interior can contain hidden gemstone-quality crystals.

Field identification & locations

Identify in the field by looking for rounded, bumpy, or 'cauliflower-like' exterior textures; they often feel lighter than other rocks of the same size if they are hollow. Commonly found in desert regions or limestone beds.