'who am I?'

So, I wrote a poem, it's more of a riddle but quite easy, or at least I think so. This is more a draft anyway. Cold and hard and flat, I gleam for those who love themselves, And cloud for those who love others. I tell no lie For is it not better to speak the hard-hearted truth Than to suffocate in the warm folds of delusion and vanity? I have no image of my self to present to you, But look upon your own face and answer me: Who am I? Not sure if it relates to anything or whatever, I just came up with it and thought I'd share.