Answer:
They're up near the sky, on something very tall. Sometimes they die, only then do they fall.
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.
It's like food but water kills it. What is it?
I do not breathe, but I run and jump. I do not eat, but I swim and stretch. I do not drink, but I sleep and stand. I do not think, but I grow and play. I do not see, but you see me everyday.
Each of these ends in a kettle full of precious metal and the double variety is quite awesome