Spiky on the outside, sweet within A crown on top, where do I begin?

I am born when nothing divides, yet found in all that lives and dies. I have no weight, but tip the scale, the silent glitch in every law. You seek to name me, but beware, to know me is to say I'm not there.

I make shelter, but I am not made of walls. You might see me in rain.

Old or modern, I serve to add color or flavor. I can be found in the supermarket or a flower. If you're low on money, I may not be in your favor.

I look like a mouth, but I am not a body part. People often dive here.