Seams must be addressed on a type of material basis. Most granites are very difficult to top polish. Synthetic stones cannot be top polished. Also, most materials can chip and flake and are not perfectly flat. If the material will not bond well or if we expect movement in the sub structure we will not solid glue the seam. It will eventually crack and the seam will shift. In most cases, we first bevel the seam edges to hide these variations and then we will soft glue the seam so it can move without cracking.
If the material can be top polished, AND if the substructure is solid enough, And If the material bonds well, we can hard glue the seam and then top polish it.
There will always be color and movement variations that will make the seam visible.
Please understand that this is a seam in a natural stone or quartz material. Seams in glass are beveled for this reason. We will do our very best to make the best seam possible