Phaneritic's a term usually used to refer to igneous rock grain size. It means that the size of matrix grains in the rock are large enough to be distinguished with the unaided eye as opposed to aphanitic (which's too small to see with the naked eye). This texture forms by slow cooling of magma deep underground in the plutonic environment. It may also appear in, and be applied to metamorphic rocks, with the same definition.… (More on Phaneritic)