sedimentary
Geode (Unopened)
Silica-rich Concretion (SiO2)
AI-generated identification · may be incorrectHardness: 7 (outer shell), Color: Dull brown or gray exterior with a bumpy/cauliflower texture, Luster: Earthy, Structure: Spherical or subspherical hollow nodule
- Luster
- Earthy, Structure: Spherical or subspherical hollow nodule
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Physical properties
Hardness: 7 (outer shell), Color: Dull brown or gray exterior with a bumpy/cauliflower texture, Luster: Earthy, Structure: Spherical or subspherical hollow nodule
Formation & geological history
Formed in sedimentary rock cavities (such as limestone) or volcanic ash beds where mineral-rich water precipitates crystals over millions of years.
Uses & applications
Primarily used for educational purposes, mineral collecting, lapidary art, and home decor once cracked open to reveal internal crystals.
Geological facts
The word geode comes from the Greek word 'Geoides' meaning earth-like. Many geodes contain quartz, amethyst, or calcite crystals inside that have never seen light until opened.
Field identification & locations
Identify by its rounded shape, lightweight feel compared to solid rocks of the same size (indicating a hollow center), and distinct 'cauliflower' surface texture.
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