Answer:
The more I appear The less you see. So riddle me this: What could I be?
What loses its head every morning only to get it back every night?
What can you never get rid of when you lose it?
People want it, and when they have it, they use it by giving it
What is seen in the water and in the sky? It is part of the rainbow and can be in your eye
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.