A large crystal that is surrounded by a finer-grained matrix in a metamorphic rock. Porphyroblasts form by the recrystallization of existing mineral crystals during metamorphism. They are analogous to phenocrysts in igneous rock.
/ˌpɔːfəˈrɒdʒɪˌnaɪt/ noun 1. (sometimes capital) a prince born after his father has succeeded to the throne
/ˌpɔːfɪˈrɒpsɪn/ noun 1. a purple pigment occurring in the retina of the eye of certain freshwater fishes
[pawr-fuh-roid] /ˈpɔr fəˌrɔɪd/ noun 1. a rock resembling . 2. a sedimentary rock that has been metamorphosed so as to leave some original crystals in a fine-textured, layered matrix. /ˈpɔːfɪˌrɔɪd/ adjective 1. (of metamorphic rocks) having a texture characterized by large crystals set in a finer groundmass noun 2. a metamorphic rock having this texture
[pawr-fuh-ree] /ˈpɔr fə ri/ noun, plural porphyries. 1. a very hard rock, anciently quarried in Egypt, having a dark, purplish-red groundmass containing small crystals of feldspar. 2. Petrology. any igneous rock containing coarse crystals, as phenocrysts, in a finer-grained groundmass. [pawr-fuh-ree] /ˈpɔr fə ri/ noun 1. (Malchus) a.d. c233–c304, Greek philosopher. /ˈpɔːfɪrɪ/ noun (pl) -ries […]