NordStar, there doesn't need to be a historical reference, necessarily. We are a living religion, not a fan-base for the ancient ways. Our world is different than the Norse's and I believe that the gods have grown with us.
That said, there aren't many stones associated with gods that I know of. Having a "god of [blank] " or things associated with a god (and that god alone) is somewhat foreign to Heathenism, and is more found in Greek/Roman Paganism and Wicca. The only stone that I would consider tied to a particular god would be fulgarite, as it is essentially solidified lightning.