We have a pretty large granite countertop in our kitchen. The main
part constists of 3 pieces of stone. There seems to be some type of
grout sandwiched between the pieces. The problem is that due to
settling of an addition to the house right under one of these
junctions, the grout has come out of that seam. Can one use any type
of grout or is there a special type of material used for this
application?

Thanks