The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. In this book, the authors present current research in the study of the metamorphic history and composition of garnet. Topics discussed include rare-earth garnets and their role in modern electronics; the characterisation of garnet and its use in tracing the metamorphic evolution of three selected calc-silicate and skarn deposits; phonoton spectroscopy of yttrium-rare earth-aluminium garnet solid solutions (YAG:Re); the use of garnet as a mineral exploration tool; vibrational spectroscopy of natural garnet and photonic solids and their connection to garnets