Answer:
What is it that has four legs, one head, and a foot?
I have rivers without water. Forests without trees. Mountains without rocks. Towns without houses.
Not born, but from a Mother's body drawn. I hang until half of me is gone. I sleep in a cave until I grow old. Then valued for my hardened gold.
I cost no money to use, or conscious effort to take part of. And as far as you can see, there is nothing to me. But without me, you are dead.
Slayer of regrets, old and new, sought by many, found by few.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.