Answer:
Thirty men and ladies two, gathered for a festive do; Dressed quite formal, black and white; soon movement turned to nasty fight.
I am seen in the water. If seen in the sky, I am in the rainbow, a jay's feather, and lapis lazuli.
Two brothers we are, great burdens we bear. All day we are bitterly pressed. Yet this I will say, we are full all the day, and empty when go to rest.
Flat as a leaf, round as a ring. Has two eyes, can't see a thing.
A type of hammer that brings a room to order.
If it’s information you seek, come and see me. If it’s pairs of letters you need, I have consecutively three. What am I?