What is a porphyritic igneous rock?

Thanks for the A2A. Igneous rock is formed through the cooling and solidification of magma or lava and is one of the three main rock groups, the two others being sedimentary and metamorphic. The word igneous comes from the Latin term ignis, which means fire. read more

Most types of igneous rocks will display some degree of porphyritic texture. Porphyritic igneous rock will have a distinct difference in the size of the crystals with at least one group of crystal being obviously larger than another group. read more

Porphyritic is an adjective used in geology, specifically for igneous rocks, for a rock that has a distinct difference in the size of the crystals, with at least one group of crystals obviously larger than another group. read more

Any rock that has a porphyritic texture. A porphyritic texture is one that is characterised by large crystals (phenocrysts) in a finer groundmass (aphanitic part). So, many rocks are porphyritic: andesite, granite and even some basalts. read more