What does a Riddler yell when they see an absurd answer?

I bite the ocean floor, but never chew, clinging to earth beneath the blue. Though born of iron, I sleep in sand, holding giants with one hand.

I reveal the world when I lose my veil. I reflect you back when I’m dressed. I am meant for seeing, not for leaving. I stand where inside meets out.

I speak with no sound at all, Yet answer every call; I open doors, page by page, To lives from every age.

When bought I am black, when burnt becomes red, and white when cooled. Who am I?