# Geode or Agate?

**URL:** <https://boards.straightdope.com/t/geode-or-agate/389706>\
**Category:** Factual Questions\
**Created:** [January 27, 2007, 11:50am UTC](https://boards.straightdope.com/t/geode-or-agate/389706 "2007-01-27T11:50:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [January 27, 2007, 11:50am UTC](https://boards.straightdope.com/t/geode-or-agate/389706/1 "2007-01-27T11:50:00Z")

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Anyone know the difference between these two rocks? I’ve never been able to discern a difference when (a) seeing pictures in rock books nor (b) seeing these in shops with other polished gems. To me, agate always comes as slices - resembling cross sections from geodes. Is this correct, or are they two distinctly different things?

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**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\
**Post date:** [January 27, 2007, 12:06pm UTC](https://boards.straightdope.com/t/geode-or-agate/389706/2 "2007-01-27T12:06:30Z")

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[Agate](http://www.gemstone.org/gem-by-gem/english/agate.html)

[Lake Supperior Agate (Not cut)](http://www.dnr.state.mn.us/education/geology/digging/agate.html)

[Lake Supperior Agate Cut](http://www.lakesuperioragates.net/)

[Geode](http://www.isgs.uiuc.edu/servs/pubs/geobits-pub/geobit3/geobit3.html)

[Geode Again](http://www.igsb.uiowa.edu/browse/geodes/geodes.htm)

You can see the Agate is good looking on the outside and is in banded layers of quartz. The geode is a dull ugly rock on the outside that has partialy filled in with quartz crystal. The pages given fill in the details well.

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**Author:** ![TristanVT](https://avatars.discourse-cdn.com/v4/letter/t/a6a055/32.png) [@TristanVT](https://boards.straightdope.com/u/TristanVT)\
**Post date:** [January 30, 2007, 11:46pm UTC](https://boards.straightdope.com/t/geode-or-agate/389706/3 "2007-01-30T23:46:25Z")

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[QUOTE=Jinx]  
Anyone know the difference between these two rocks? I’ve never been able to discern a difference when (a) seeing pictures in rock books nor (b) seeing these in shops with other polished gems. To me, agate always comes as slices - resembling cross sections from geodes. Is this correct, or are they two distinctly different things?  
[/QUOTE]

Agate is quartz in a cryptocrystaline form. Geodes are primarily qaurtz in various forms, an outer layer of agate and crystaline quartz inside.