Riddle of the day

[mshrmit]

If you touch me, I am cold and resistant at first, but then crumble in your fingers. I bubble out of the ground in a frozen lava flow. Bumps and ridges mar my dark brown surface. White sprinkles are my final decoration. What am I?

Hint: We went on a nature walk today and had to describe something we saw.

Comments

Re: I know! I know!

[mshrmit]

You're right!