amygdaloid

  1. Adjective.  Shaped like an almond.
  2. Noun.  A variety of trap or basaltic rock, containing small cavities, occupied, wholly or in part, by nodules or geodes of different minerals, especially agates, quartz, calcite, and the zeolites. When the imbedded minerals are detached or removed by decomposition, it is porous, like lava.

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This entry was last updated on RefTopia from its source on 3/20/2012.