Alright. [He unwinds the finger from his hair. He's never had to explain this before, nor had it explained to him in that other life -- Liam had taught himself from a book.]

When you use magic, you are drawing from within yourself, not from the environment. [Hence why personality has such a strong effect on what colour one takes to.] For a spell like this, it isn't necessary to draw upon any specific type of energy. Concentrate, look within; when you find it, you will know.