Answer:
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.
What goes in the water red, and comes out black?
Runs smoother than any rhyme, loves to fall but cannot climb.
I work when I play and play when I work.
I'm the source of all emotion, but I'm caged in a white prison.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.