That looks like a White Carrara Marble. I'd say it's definitely marble. See the lines going across the island and meandering behind the shelves? Quartz is usually a much smaller patter and doesn't have so much variation.

Of course it can be quartz! Cambria makes uber-realistic stone replicas in quartz with patterns that don't repeat for 12 feet!!

Additionally, Marble is highly porous and definitely not recommended for a backsplash material... Even with surface treatments (which over time you will neglect to do and ruin the marble with your tomato sauce!!) I would never sell a marble backsplash to a customer... However, kitchens built for magazine spreads like this often chose form over function and so it is not impossible that it is marble I guess..

Yes, it's technically possible to have quartz in this kitchen, but this specific stone is most likely marble.

LOL.... Ok... I'm not one to argue with elders... Thanks for the info Grannie.