white.

Black

I think if you're going to iron spindles and a dark handrail then I would be sticking with the white marble. The clean contrast will create a striking visual without it looking too busy. So many times I have worked with clients that wanted their projects to be so unique and interesting, that they're tempted to cram too many features into one space. I'm usually the one reeling their choices in, so we're careful to create a space that offers 1-2 focal points at the MOST. In the end, we achieve a look that boasts strength, balance and impact & that will stand the test of time. There's a saying that less is more and I think it applies to this situation. Congrats on the reno, it's going to look just stunning!

Hey There: go with the off white/beige stone - this will go best with your interior design. Also, you do have all the door casing and hand rail the same wood and finish - keep it that way please...

Good Luck with your project - it looks already stunning.