mineral
Quartz Geode
Silicon Dioxide (SiO2)
Hardness: 7 on the Mohs scale. Color: Clear to white crystals within a brownish-grey chalcedony/limestone outer shell. Luster: Vitreous to glassy for the internal crystals, dull for the outer matrix. Crystal structure: Trigonal. Cleavage: None.
- Hardness
- 7 on the Mohs scale
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Physical properties
Hardness: 7 on the Mohs scale. Color: Clear to white crystals within a brownish-grey chalcedony/limestone outer shell. Luster: Vitreous to glassy for the internal crystals, dull for the outer matrix. Crystal structure: Trigonal. Cleavage: None.
Formation & geological history
Formed in hollow cavities in sedimentary or volcanic rock where mineral-rich groundwater or hydrothermal fluids seep in and slowly deposit silica crystals over millions of years.
Uses & applications
Used in mineral collecting, decorative display pieces, metaphysical practices, and lapidary arts.
Geological facts
Geodes start as bubbles in volcanic lava or animal burrows/nodules in sedimentary layers. Over time, silica-bearing solutions coat the inside, creating a hollow cavity lined with sparkling quartz crystals.
Field identification & locations
Easily identified by its spherical or nodular exterior with a hollow interior lined with sparkling crystal points. Commonly found in regions with limestone deposits or volcanic rock formations worldwide, such as Morocco, Mexico, and the US (e.g., Iowa, Indiana, Kentucky).
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FeO(OH)·nH2O / FeO(OH)
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Septarian Pebble
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Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral