As natural minerals, silica and silicates constitute by far the largest part of the earth's crust and mantle. They are equally important as raw materials and as mass produced items. For this reason they have been the subject of scientific research by geoscientists as well as by applied scientists in cement, ceramic, glass, and other industries. Moreover, intensive fun damental research on silicates has been carried out for many years because silicates are, due to their enormous variability, ideally suited for the study of general chemical and crystallographic principles. Several excellent...