sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2) in Geode form
Hardness: 7 on Mohs scale; Color: White to grey botryoidal crystals; Luster: Vitreous to waxy; Structure: Hexagonal crystal system (microcrystalline/cryptocrystalline); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- White to grey botryoidal crystals
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 7 on Mohs scale; Color: White to grey botryoidal crystals; Luster: Vitreous to waxy; Structure: Hexagonal crystal system (microcrystalline/cryptocrystalline); Specific Gravity: 2.65
Formation & geological history
Formed when mineral-rich groundwater seeps into cavities in sedimentary limestone or volcanic ash; over millions of years, crystals precipitate on the cave walls. This specimen likely originates from the Keokuk or Las Choyas regions.
Uses & applications
Primarily used for geological education, home decor, and spiritual/metaphysical collecting. High-quality clusters may be used in jewelry.
Geological facts
Geodes are essentially 'vugs' or hollow rocks; they often look like ordinary round stones on the outside but contain magnificent crystal treasures inside. Some contain rare minerals like goethite or calcite.
Field identification & locations
Identified by a lumpy, cauliflower-like exterior and a hollow interior. Commonly found in riverbeds or desert regions of Morocco, Mexico, and the United States (Iowa, Indiana).
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