Element Girls - Giulietta M Spudich

Susie, Elizabeth, Tess and Amelia have been friends for as long as they can remember. But things are changing this year, and thier friendships are being tested like never before. When Amelia suddenly vanishes, the remaining three friends find themselves jetting to Hawaii with a wallet that produces unending cash. They also discover that the amulets they wear as a symbol of their friendship give them elemental powers. But will their new powers be enough to save Amelia from a dangerous sorcerer, who is also her estranged father? Can they face dangers that they didn't even know existed outside of books?