Answer:
What kind of coat can only be put on when wet?
Curtail me thrice I am a youth; behead me once a snake; complete I'm often used in truth when certain steps you'd take.
Lovely and round, I shine with pale light, Grown in the darkness, a ladyβs delight.
Glittering points that downward thrust. Sparkling spears that never rust.
I go up and down at the same time. Up towards to sky and down towards the ground
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.