porphyry Meaning, Definition & Usage

  1. noun any igneous rock with crystals embedded in a finer groundmass of minerals
    porphyritic rock.

WordNet

Por"phy*ry noun
Etymology
F. porphyre, L. porphyrites, fr. Gr. like purple, fr. purple. See Purple.
Wordforms
plural Porphyries
Definitions
  1. (Geol.) A term used somewhat loosely to designate a rock consisting of a fine-grained base (usually feldspathic) through which crystals, as of feldspar or quartz, are disseminated. There are red, purple, and green varieties, which are highly esteemed as marbles.

Webster 1913