Answer:
Looks like water, but it's heat. Sits on sand, lays on concrete. A play on the eyes, but it's all lies.
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.
Above all things have I been placed Thus have I, a man disgraced. I describe sunlight or lock But after all, I'm just a rock
If a man carried my burden, he would break his back. I am not rich, but leave silver in my track.
Break it and it is better, immediately set and harder to break again.
What covers its face with its hands, speaks no language, yet most known what it's saying?