Is Kristen Stewart's and Emma Stone's hair naturally wavy hair
 

I'm wondering because they have beautiful waves when their hair is wavy.

It's probably curled. That's how it is with most celebrities these days.

They have hair stylists that's why their hair style looks naturally and beautifully wavy. I think Kristen Stewart's hair stylist is Adir Abergel. He shares hair tips on twitter and to beauty mags sometimes. :)