The Ruby Princess Runs Away (Jewel Kingdom #1)

In the Jewel Kingdom, four girls rule: Roxanne is the Ruby Princess, Sabrina is the Sapphire Princess, Emily is the Emerald Princess, and Demetra is the Diamond Princess. But soon-to-be Ruby Princess Roxanne isn't so sure she's ready to be royalty. She decides to run away, but before she can get very far, she learns of a plot to take over the Jewel Kingdom.