porphyroid

[ pawr-fuh-roid ]
/ ˈpɔr fəˌrɔɪd /

noun

a rock resembling porphyry.
a sedimentary rock that has been metamorphosed so as to leave some original crystals in a fine-textured, layered matrix.

Origin of porphyroid

First recorded in 1790–1800; porphyr(y) + -oid

Example sentences from the Web for porphyroid

  • Pumice and trachyte are the most common rocks around this mountain, and these are augitic or porphyroid.

British Dictionary definitions for porphyroid

porphyroid
/ (ˈpɔːfɪˌrɔɪd) /

adjective

(of metamorphic rocks) having a texture characterized by large crystals set in a finer groundmass

noun

a metamorphic rock having this texture