porphyry

• POS: Noun
• HYPHEN: por=phy=ry

CIDE DICTIONARY

porphyry, n. [F. porphyre, L. porphyrites, fr. Gr. like purple, fr. purple. See Purple.].

 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.  [1913 Webster]

Porphyry shell (Zoöl.), a handsome marine gastropod shell (Oliva porphyria), having a dark red or brown polished surface, marked with light spots, like porphyry.

OXFORD DICTIONARY

porphyry, n. (pl. -ies)
1 a hard rock quarried in ancient Egypt, composed of crystals of white or red feldspar in a red matrix.
2 Geol. an igneous rock with large crystals scattered in a matrix of much smaller crystals.

Derivative

porphyritic adj.

Etymology

ME ult. f. med.L porphyreum f. Gk porphurites f. porphura purple