Squigly Squigly's Brain Teasers

Question:

Rough and gray as rock,
I'm plain as plain can be.
But hidden deep inside there's great beauty in me.
What am I?

Answer:

An oyster.

Try another Brain Teaser:

An electric train is going 40 mph north, the wind is blowing 60 mph south. Which way is the train's smoke blowing?