mineral

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in Geode

Hardness: 7 on Mohs scale; Color: Clear to white crystals within a gray/tan host rock; Luster: Vitreous (glassy) crystals with a dull/earthy exterior; Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Color: Clear to white crystals within a gray/tan host rock
Luster: Vitreous (glassy) crystals with a dull/earthy exterior

Identified June 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed via the precipitation of mineral-rich groundwater within hollow cavities in volcanic ash or sedimentary limestone over millions of years.

Uses & applications

Primarily used for decorative purposes, crystal healing, educational displays, and as a popular entry-level mineral for collectors.

Geological facts

Geodes are often called 'thunder eggs' when they are solid or have specific shapes. The word 'geode' comes from the Greek word 'geoides' meaning 'earth-like'.

Field identification & locations

Identify in the field by looking for rounded, bumpy, potato-like nodules that feel lighter than they look (indicating a hollow center). Common in desert regions of the SW United States, Brazil, and Morocco.

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Arenite (SiO2 based)

sedimentary

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Nephrite Jade

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Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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Metamorphic Rock

Green Apatite on Albite

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mineral