Answer:
I am a precious stone, as clear as a diamond. Though you can walk on water with my power, try to keep me, and I'll vanish in an hour. What am I?
I am a path between high natural masses; remove the first letter to get a path between man-made masses.
Turns me on my backs and open up my stomach. You will be the wisest of men though at start a lummox.
I am a person who pretends to be someone else
I am an object which is used in baseball during the day I can't be seen at all
I am rarely touched but often held. If you are smart you'll use me well. What am I?