Answer:
Can not be bought, Can not be sold, Even if it's made of gold. What is it?
What type of house weighs the least?
Only one color, but not one size. Stuck at the bottom, yet easily flies. Present in sun, but not in rain; doing no harm, and feeling no pain. What am I?
I am rarely touched but often held and if you are smart you'll use me well.
I break down buildings, I crumble mountains but you can't see me. What am I?
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.