sedimentary
Unopened Geode
Geode (containing various mineralization like Quartz SiO2)
Hardness: 7 (inner quartz); Color: Earthy brown/orange exterior from iron staining; Luster: Dull/earthy exterior; Crystal structure: Trigonal (internal); Cleavage: None; Specific Gravity: Approx 2.65
- Hardness
- 7 (inner quartz)
- Color
- Earthy brown/orange exterior from iron staining
- Luster
- Dull/earthy exterior
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Physical properties
Hardness: 7 (inner quartz); Color: Earthy brown/orange exterior from iron staining; Luster: Dull/earthy exterior; Crystal structure: Trigonal (internal); Cleavage: None; Specific Gravity: Approx 2.65
Formation & geological history
Formed via secondary mineral precipitation within hollow vugs or cavities in sedimentary or igneous rocks, often through groundwater action over millions of years (often Jurassic to Tertiary periods).
Uses & applications
Commonly used for educational purposes, mineral collecting, lapidary art, and home decor once sliced or cracked open.
Geological facts
Geodes are like nature's lottery tickets; you don't know what crystals are inside until you crack them. The term comes from the Greek 'geoides' meaning earth-like.
Field identification & locations
Identify by a round or egg-like shape with a bumpy, cauliflower-like texture and a lower weight than a solid rock of the same size. Commonly found in deserts or river beds in regions like the US Midwest or Morocco.
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