The texture of an igneous rock formed from magma that cooled slowly below the earth surface is non-vesicular and coarse.
Phaneritic:
It means visible grains. These textures are typically found in intrusive igneous rocks, these rocks crystallized slowly deep underground.
Slow cooling down of magma allows minerals to have more time to grow and form large crystals. This gives the intrusive igneous rock a coarse-grained or phaneritic texture.
Therefore, the texture of an igneous rock formed from magma that cooled slowly below the earth surface is non-vesicular and coarse.