This book has presented the current state of research on the transformation process of pyrite and the significance of further research (see chapter “Current Research on Pyrite and Its Heating Transformation Process”). Since the heating behavior of pyrite in air is more universal and applicable, as well as the reliability of XRD to study pyrite (England et al. 1999; Eneroth and Koch 2003; Yakovleva et al. 2003) and transformation processes in minerals (Ono 2007; Perrillat 2008), Wang et al. (2014) focused on natural pyrite, using XRD technique, to reveal the mineral phases and their paragenetic association during the heating transformation process of pyrite from room temperature to 1250 °C in air. The research results are not only important for the mineralogical and industrial mineralogy studies of pyrite and related minerals, as well as the beneficiation, purification, and industrial applications of pyrite, but also provide a typical example for the study of phase changes during the heating process of metallic minerals.