I have always considered Moonstone as my favourite stone. I love particularly the white Moonstone, because just as its name implies, it has a floating light effect and sheen called adularescence, compared to the light of the moon. In this photograph, look at the stones in the middle and you will know what I mean.Every stone has this moon-light effect but you have to tilt it at different angles to see.
I even have a very delicate 925 Silver ring from Japan which has a tiny moonstone set on it. :)