The emerald quest - Gill Vickery

When the six sister-witches stole the DragonQueen's jewels of power, they banished the dragons from their home in the land of Tulay. Before the dragons left, they took with them a human child as hostage. Tia has been raised by the dragons and considers them her family. She is appalled to learn that her own human mother is one of the sister-witches who are now the despotic rulers of Tulay. Tia decides she will prove herself to be a true DragonChild by retrieving the jewels, with the aid of her DragonBrother Finn.
In this first exciting adventure, Tia goes after the jewel that gives its possessor the power to control beasts. The second story, The Opal Quest, is published in March 2013.