Solving tasks related to the development of technologies for thermal processing of vermiculite concentrates requires the use of coefficients associated with their physical-technical properties such as degree of expansion, porosity, internal and external friction, optical properties etc. Although there exist a number of information resources in this field, a lot of data is missing. This paper provides important and relevant information – both new as well as partly published earlier – obtained by experiments or analytical physical modelling. The results of conducted research supplement the existing data about physical properties and constants of vermiculite with new topical information.