Answer:
What has a bottom right at the top?
A certain wizard resided in a city made from this gemstone.
I am the heart that does not beat. If cut, I bleed without blood. I can fly, but have no wings. I can float, but have no fins. I can sing, but have no mouth.
Something wholly unreal, yet seems real to I. Think my friend, tell me where does it lie?
What has 13 hearts but none beat?
It weighs next to nothing but no one can hold it for long. What is it?