Here's why:

* Large Crystal Size: Granite is an igneous rock that cools slowly underground. This slow cooling allows the mineral crystals to grow large.

* Light Pink Color: The pink color in granite is usually due to the presence of feldspar, a common mineral that can range from white to pink.

Other possibilities:

While granite is the most likely answer, other light pink rocks with large crystals exist:

* Pegmatite: This is a type of igneous rock that can have very large crystals, sometimes even exceeding a foot in size. It can also be pink due to feldspar.

* Syenite: This igneous rock is similar to granite but contains less quartz. It can be pink due to the presence of alkali feldspar.

If you have a picture of the rock, it would be easier to determine its specific type.