Answer:
What can you fold but not crease?
I make you weak at the worst of all times. I keep you safe, I keep you fine. I make your hands sweat. And your heart grow cold. I visit the weak, but seldom the bold.
I don't have eyes, but once I did see. Once I had thoughts, but now I'm white and empty.
I dig out tiny caves and store gold and silver in them. I also build bridges of silver and make crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs my help. Yet many people are afraid to let me help them.
It is weightless, you can see it. If you put it in a barrel it will make it lighter?
What is so fragile that saying its name breaks it?