I am not sold on granite faced fireplaces, at least with the typical highly polished finish. Maybe if it was honed.
There are a couple reasons, in my mind...since it's not currently a typical facing it might look like you used it because it is left over. It was also kind of a flashy 80's -90's thing that people did (and still do) around here, but that is usually granite tile. This was particulary disappointing when people did it to cover historic tile.
What if you did something like a honed slab of the granite on the hearth and painted the brick on the surround a color to coordinate?
Q