The Killing Crystal — Tim Myers

Griffin discovers a powerful new crystal while he and his classmates are exploring the bloody caves on a field trip away from the wizarding school, Darkthorn, but he's shocked when he learns that it is the fabled Killing Crystal, one foretold many years before. As Griffin struggles to master the crystal, he must fight to keep the powers he worked so hard to earn the year before. In the end, Griffin must tame the crystal, or risk losing everything!