The atomic ratio Si:Al in the poly(sialate) structure determines the properties and application fields. A low ratio Si:Al (1,2,3) initiates a 3D-Network that is very rigid. A high ratio Si:Al, higher than 15, provides polymeric character to the geopolymeric material. One third of Davidovits’ book, GEOPOLYMER Chemistry & Applications, is dedicated to applications. See the Chapters 18 to 26.