What igneous rocks are porphyritic?

1 Answer
Mar 3, 2016

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.

A porphyritic andesite - University of Wisconsin Department of Geosciences

There is even a rock known as a porphyry which is an ore-hosting rock that got its name simply from the fact it was porphyritic!

So remember a porphyritic rock is one with a porphyritic texture (large crystals in a finer groundmass).