Prelude of Fire (Gailean Quartet #1) by Christine E Schulze:
 
A desperate mission. Sinister sorcery. Can she find the seven prism shards to stop the world from being destroyed?

Ashlai, a young Fyre mage who can harness powers of flame from the sun, yearns to know about her kin. Her adoptive elven father refuses to let her travel abroad with her brother, and she despairs of ever knowing who she really is. But when the new king’s vicious spell attacks her forest home, she flees toward that unknown past—and an uncertain destiny—guided only by the strange melody in her head and a piece of broken prism.

Determined to save the land from the enchanted drought burning everything in its path, Ashlai searches for six other magical fragments to overthrow the ruthless king. With the help of a shape-shifting thief, two squabbling bards, and a snarky water elf, she races toward a perilous confrontation…and a life-changing truth.

Can Ashlai fight fire with fire to defeat the devastating spell before it consumes the entire land? And can she survive the secrets she discovers without losing her new friends, her family, and even herself?