Answer:
Deep, deep, do they go. Spreading out as they go. Never needing any air. They are sometimes as fine as hair.
Glittering points that downward thrust. Sparkling spears that never rust. What am I?
A large oasis in the desert. Come with cash and leave with none.
I am an instrument capable of making numerous sounds but cannot be touched or seen. What am I?
I am all around yet to me you are half blind. Sunlight makes me invisible and difficult to find.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.