| porphyry | Origin: F. Porphyre, L. Porphyrites, fr. Gr. Like purple, fr. Purple. See Purple. <geology> 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. <zoology> Porphyry shell, a handsome marine gastropod shell (Oliva porphyria), having a dark red or brown polished surface, marked with light spots, like porphyry. Source: Websters Dictionary (01 Mar 1998) |
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