regant:
We used a calacatta gold marble slab for our tub surround and counter tops. We have been using the bathroom for only about 2 1/2 months, but so far, we love it!

Thanks for the reply and photograph. Your bathroom looks lovely - in particular the combination of tile and marble in particular.

We're familiar with the marble slab for the vanity top but we had in mind using the slab on the wall above the tub (from the top of the tub to the ceiling). This is the area we are dithering about. Any thoughts would be appreciated.

Yup it will be expensive. In a search engine I did search words marble slab tub surround and use the IMAGE search instead of the usual search box and see what you find. These two are big slabs in showers.

http://brookegiannetti.typepad.com/.a/6a00e554d7b827883301156e87491c970c-500wi

http://www.luxurystone.com/img/LuxuryStoneBath03.jpg

natenvalsmom - What is the color/name of the mozaics on the wall?

Ginger25:
The mosaic tile on the walls of our bathroom is Vintage Glass by Walker Zanger, and the color is "Zinc Lustre."

I actually think the 12x24" tile idea is a good one, especially if the marble has some movement in it to distract from the seams. It will be gorgeous.

I agree with na_praha, especially if you take the time and effort to lay out the tiles and plan the layout so the veining flows well.

Thanks to na_praha and writersblock for your comments.
We were made aware of porcelain tiles that look just like Calacatta by a GardenWeb posting by "blondelle". The posting made reference to the "Rex" website and the "I-Bianchi Di Rex" tiles. The website is http://www.rex-cerart.it/en/proda-3-1.asp.
We are now looking at 24"x48" tiles in this range and think they will look very impressive. We are getting a sample of the polished version and if we like it we will have to take care with the layout. We have more or less given up on a marble slab because of the cost and complication of getting it here in Atlantic Canada.
We have been quoted $50/sq ft (without installation)for the 24"x48" tiles. They have to be specially ordered from Italy, but this seems excessive. We are looking at a smaller tile of the same pattern for the floor (perhaps 18"x18"). Maybe it is the very large size that drives up the cost.

I am about to purchase carrara marble for my shower. I have an option to purchase Q-seal marble which is sealed at the factory. Does anyone have any experience with this? I am concerned that the marble will discolor (turn yellow)

Thanks!