different between porphyry vs phenocryst

English

From Old French porfire, from Ancient Greek ?????????? ????? ("purple stone").

porphyry (countable and uncountable, plural porphyries)

(geology) a hard igneous rock consisting of large crystals in a fine-grained matrix
1. A purple-red rock of this kind.

phenocryst (plural phenocrysts)

(mineralogy) Any relatively large crystal embedded in a more fine-grained or glassy igneous rock
- 1965, Gordon A Macdonald and Takashi Katsura, Eruption of Lassen Peak, Cascade Range, California, in 1915: Example of Mixed Magmas, Geological Society of America Bulletin 76 (5), pages 475:
  Some of the feldspar phenocrysts are more than 1 cm long, but most are less than 5 mm.

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