Large masses of magma that solidify far below the surface form igneous rocks that have a phaneritic texture.

Here's why:

* Phaneritic texture means the rock has large, visible crystals. This happens because the magma cools slowly deep underground, giving the crystals ample time to grow.

* Intrusive igneous rocks are formed from magma that solidifies below the surface. They are characterized by their phaneritic texture.

Examples of intrusive igneous rocks include granite, gabbro, and diorite.