Definition of geode in US English:



  • 1A small cavity in rock lined with crystals or other mineral matter.

    • ‘Sphalerite in crystals to 8 cm and cleavage masses to 30 cm across occurs in geodes of the well-known southeastern Iowa localities, such as those around Keokuk.’
    • ‘One case has a selection of crystal-lined geodes, several filled with amethyst, from the Josini area of northern KwazuluNatal in South Africa.’
    • ‘Mordenite lines most of the geodes as the typical fine hairlike crystals of the species.’
    • ‘Most of the thirty-two pages on Moroccan agate are color plates of superb geodes with fantastic patterns and inclusions.’
    • ‘Colorless quartz crystals lining geodes have also been found at approximately 300 feet below the trail at the South Overlook locality.’
    • ‘Some visitors gather around the sparkling amethyst geodes or the shining pyrite crystals.’
    space, chamber, hollow, hole, pocket, pouch
    View synonyms
    1. 1.1 A rock containing a cavity lined with crystals or other mineral matter.
      • ‘It's centered around this hill with all these geodes, and a stone archway at the top.’
      • ‘‘This is a once-in-a-lifetime opportunity,’ exclaimed a collector from the Keokuk area who was working beside me splitting geodes out of shale.’
      • ‘They are different from geodes in that they have a solid center, often displaying a great contrast between the rocky shell of brown and the milky white and clear crystal center.’
      • ‘It's a teeny one… but like all geodes there is a whole different world inside.’
      • ‘Two adjacent geodes from the same piece of shale could be cracked open, and one would be lined with brown calcite, the other with quartz.’
      • ‘In the extreme and startling contrast between its outer and inner life, it resembles some kind of weird rock or geode that, split open, reveals a spectacular mineral formation.’
      • ‘It is a geode having a small U-shaped cavity crammed with tiny quartz crystals.’
      • ‘He opened one of the largest geodes and gave half to Hart.’
      • ‘Joy likens the house to a geode, the coarseness of the rough steel exterior contrasting with the refinement of the interior.’
      • ‘Do I not take responsibility for my stress when I lift the geode and consciously transform the stress energy into something healthier for my physical body?’
      • ‘People love to do camping here because of the fascinating aura and to grab 15 pounds of agates, geodes and quartz that anyone can gather and take to home.’


Late 17th century: via Latin from Greek geōdēs ‘earthy’, from gē ‘earth’.