Gone in a flash

Question: Once you are in my sight, you are gone in a flash, and people tend to use me for cash. I am often used as a dire assist, and people often believe that I cause harm, when I am but its catalyst. What am I?

Question: What tastes better than it smells?

Question: What goes in the water black and comes out red?

Question: What asks but never answers?

Question: To many, I am life's source. I am also its most valuable resource. I create and burn my own precious element, and my destruction will be my punishment. What am I?

Question: I have 6 faces and 21 eyes, but can't see a thing. What am I?