Answer:
What is that which, though black itself, enlightens the world without burning?
When young, I am sweet in the sun. When middle-aged, I make you gay. When old, I am valued more than ever.
A certain wizard resided in a city made from this gemstone.
The weapon of choice to create the biggest shock.
Each morning I appear to lie at your feet, all day I follow no matter how fast you run. Yet I nearly perish in the midday sun.
I have two eyes in the front and a lot of eyes on my tail