Adjective
Relating to, or resembling, porphyry, that is, characterized by the presence of distinct crystals, as of feldspar, quartz, or augite, in a relatively fine-grained base, often aphanitic or cryptocrystalline.
Source: Webster's dictionaryGabbro is usually equigranular in texture, although it may be porphyritic at times, especially when plagioclase oikocrysts have grown earlier than the groundmass minerals. Source: Internet
In this connection we may repeat what has been said above about the corrosion of porphyritic minerals in igneous rocks. Source: Internet