it sounds like what you want, though, is a marble-like surface that reflects an image.

You need to be careful and not push the image all the way to white, as the reflection will be added on top of the diffuse color of the surface. By making the diffuse color max out at a light gray and lighting appropriately, you can make the marble SEEM white while still maintaining detail in the reflection.

Remember, we see whites not only as a result of high value but also because of contrast with darker objects in the scene.

-- Mark