Answer:
I dig out tiny caves and store gold and silver in them. I also build bridges of silver and make crowns of gold. Sooner or later everybody needs my help yet many people are afraid to let me help them.
I am a way to say goodbye to your sweetheart
I run smoother than any rhyme I love to fall but cannot climb.
I stand in one place yet I fill a whole room. I can be filled with molten rock and come in every hue.
I rise and fall no matter what, only at finals rest do I not budge. What am I?
Give it food and it will live, give it water and it will die.