mineral

Quartz Geode

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Clear to white internal crystals with a gray/brown outer rind; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Luster: Vitreous (glassy)

Identified April 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities within volcanic or sedimentary rocks. Over millions of years, mineral-rich groundwater seeps into these hollow spaces, depositing layers of silica that eventually crystallize into quartz.

Uses & applications

Primarily used as decorative display pieces, educational specimens in geology, and in the metaphysical/collecting markets.

Geological facts

Geodes are known as 'nature's lottery' because you don't know what kind of internal crystal structure exists until they are cracked open. The word geode comes from the Greek word 'Geoides' meaning earth-like.

Field identification & locations

Identify in the field by looking for rounded, hollow-feeling stones with a bumpy, cauliflower-like outer texture. Commonly found in desert regions or limestone beds in places like Mexico, Brazil, and the Midwestern USA.