“Walk On Earth A Stranger,” by Rae Carson.
Lee Westfall has a strong, loving family. She has a home she loves and a loyal steed. She has a best friend—who might want to be something more. She also has a secret. Lee can sense gold in the world around her. Veins deep in the earth. Small nuggets in a stream. Even gold dust caught underneath a fingernail. She has kept her family safe and able to buy provisions, even through the harshest winters. But what would someone do to control a girl with that kind of power? A person might murder for it. When everything Lee holds dear is ripped away, she flees west to California—where gold has just been discovered. Perhaps this will be the one place a magical girl can be herself. If she survives the journey.