Answer:
While you were folding a letter you got me. Usually you will do whatever it takes to avoid me but now you can't help but find me.
A thousand wheels but move I do not. Call me what I am call me a lot.
I am lighter than air but a hundred people cannot lift me. Careful! I am fragile!
Taken from a mine and then locked up in a wooden case. I am used by students everyday.
I am the only word that looks the same when spelled upside down.
I am rarely touched but often held. If you are smart you'll use me well. What am I?