Answer:
I can be written, I can be spoken, I can be exposed, I can be broken.
Tool of thief, toy of queen. Always used to be unseen. Sign of joy, sign of sorrow. Giving all likeness borrowed.
Describes universities like Harvard and can be poisonous.
It cannot be seen, it weighs nothing, but when put into a barrel, it makes it lighter.
Until I am measured I am not known, Yet how you miss me when I have flown.
I always have to work with something in my eye. What am I?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?