We just had a wood stove installed, and had a hearth built to support it. The hearth is covered in river rock sliced flat with matting on the back, the contractor installed it with grout, now I am left to do the sealing, I feel like a step was missed somewhere, I want my stones to be glossy, however the grout is not sealed yet, can I use the same sealer for both and achieve the glossy finish I want on the rocks?

Since the tiles are natural stone you can use an enhancing sealer on the tiles and of course the grout. This type of sealer will enrich/darken/enhance the tiles and grout too. It'll give the tiles a sort of "wet look".

Jaz