Answer:
What types of words are these: madam, civic, eye, level?
This is in a realm of true and in a realm false, but you experience me as you turn and toss.
It's in your hand though you can not feel it. Only you and time can reveal it.
What I am filled, I can point the way. When I am empty. Nothing moves me. I have two skins. One without and one within.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.
The more of me you take, the more I appear behind you. What am I?