porphyroblast From WikiWord, the free dictionary English Contents DefinitionsRelated wordsReferences DefinitionsnounA relatively large crystal within a metamorphic rock Related wordsSynonymsfeldspargarnetmetacrystalporphyryporphyrepoikiloblastporphyriteporphyroidxenoblastphenocrystmicrophenocrystmegacrystporphyrogenemacrocrystalprotolithcrystalloclast References Wiktionary — porphyroblast Wikipedia — porphyroblast