Hey folks, A few years ago we installed a FireRock woodburning fireplace in our home, and had a mason install Pennsylvania bluestone hearth and facing (very simple: one piece hearth, three piece facing: lintel and two uprights). We've run into a couple of problems since ... First, and most important, one of the facing pieces has come loose. I can't get ahold of the mason to come and repair it, so I think I need to DIY this. I am a masonry inept, so I'd love to buy something in a tube and reattach the sucker. Is there such a product? Or should I be mixing and applying some kind of mortar? If so, what? Second, we never sealed the stone, and now there are some smoke marks (mainly behind where the steel frame of the firescreen touches the facing) and some small liquid stains on the hearth. Is there a best method of cleaning this? Favored sealant? Thanks in advance!