The tile is actually large 13 X 26 tiles that look like little tiles. It is made by Porcelanosa and the name is Nacare Blanco. They are expensive, but worth it. To save some cost on the shower, this client put the Porcelanosa tiles on the back wall only and tiled the side walls with inexpensive solid white tiles.

Here's the link to the tile:

http://www.porcelanosa-usa.com/products/nacare-blanco.html

The picture on the Porcelanosa website is not very good -- it looks much darker on their website than it really is.