Marianna Favinsky - Arizona Tile is a Tile and slab distribution company, and we don't have the opportunity to be involved in the final installation or design process. Therefore, unfortunately, we do not know which grout color was selected for this specific design. However, depending on the look you're going for we love the following Custom Building Products grout colors with Calacatta Gris and use them often in our showroom installs:

Arctic White

Ash

Driftwood - provides a more contrasting look

There are so many other grout colors that look great with this tile too! If you visit your nearest Arizona Tile location, our team can help you review grout colors and select one that will give you the aesthetic you're looking for for your project.