Answer:
A precious stone, as clear as diamond. Seek it out while the sun's near the horizon. Though you can walk on water with its power, try to keep it, and it'll vanish in an hour.
Everyone has it and no one can lose it, what is it?
I'm full of holes, yet I'm full of water.
If I have it, I don't share it. If I share it, I don't have it. What is it?
I am the yellow hem of the sea's blue skirt.
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.