geode
thumb|Quartz-filled geode, shown from inside (top) and outside (bottom)
Article
8 sectionsContents
- Formation
- Coloration
- Occurrence
- Crystal caves
- See also
- References
- Further reading
- External links
thumb|Quartz-filled geode, shown from inside (top) and outside (bottom)
A geode (; ) is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded.