4th Swiss Geoscience Meeting, Bern 2006 The application of the superspace approach in mineralogy.

Crystallography of aperiodic systems is a relatively new field in structural sciences and probably one of the most active branch in crystallography both from the theoretical and experimental points of view. Aperiodic crystals are perfectly ordered materials with long range order but lacking the three dimensional periodicity as observed in classical crystals. However, in order to recover periodicity, these structures can be described in a higher dimensional space, the (3+d)-superspace. This approach is currently applied with success for the determination and description of incommensurately modulated crystal structures (IMS). The superspace approach opens also a new scope for the characterisation of chemical bonds, for the study of phase transitions, for the classification, description and prediction of structure families and their stabilisation conditions. Natural minerals are best-suited materials for the application of the superspace formalism, because some aspects concerning their genesis and related geological aspects can be clarified at the same time. One can claim that the development of crystallography was traditionally initiated by mineralogy. The objects, which primarily instigated the mathematical description o