groundmass: see porphyry.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on groundmass from Fact Monster:

  • porphyry, igneous rock - porphyry porphyry , igneous rock composed of large, conspicuous crystals (phenocrysts) and a ...
  • basalt - basalt basalt , fine-grained rock of volcanic origin, dark gray, dark green, brown, reddish, or ...
  • Encyclopedia: Geology and Oceanography - Encyclopeadia articles concerning Geology and Oceanography.

See more Encyclopedia articles on: Geology and Oceanography

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