Hello. I have a gas fireplace in my condo and there are granite tiles around it. Well, some tiles just below the fireplace have come loose. They are still wedged in there, but I can pull them out a bit as the concrete (or whatever it is) is not longer sticking the granite tile to the fireplace. So..what do I use to reseal this granite to the fireplace? What will stick granite to smooth finished black metal? There is enough room to squirt some glue (etc) in there right now. I would hate to pull the tiles all the way off as the front still looks normal. Thanks!