ecently Kogure and co-workers published several papers reporting the stacking structures of various 2:1 layer phyllosilicates (e.g., aspidolite, Kogure et al., 2004; wonesite, Kogure et al., 2005; pyrophyllite, Kogure et al., 2006), mainly by using high-resolution TEM. However, there is ambiguity in wording that refers to the lateral displacement between two tetrahedral sheets across the interlayer regions. Zvyagin et al. (1969) used the symbol "" for this displacement, which describes the structures of pyrophyllite and talc, but no universally accepted wording was used for other 2:1 phyllosilicates or 1:1 phyllosilicates. Bailey (1984, p. 32) referred to the "layer offset" for this displacement in mica, but the original meaning of “layer offset” can be taken as the "displacement" to offset the intralayer shift of the 2:1 layer. A more precise meaning of these terms is needed that can be applied to not only the micas, but other 2:1 layer phyllosilicates also. Recommendations are also included for 1:1 layers.
Summary of recommendations of nomenclature committees relevant to clay mineralogy: report of the association internationale pour l'etude des argiles (AIPEA) nomenclature committee for 2006 / Guggenheim, S; Adams, Jm; Bain D., C; Bergaya, F; Brigatti, Maria Franca; Drits, Va; Formoso, Mll; Galan, E; Kogure, T; Stanjek, H.. - In: CLAYS AND CLAY MINERALS. - ISSN 0009-8604. - STAMPA. - 55:(2007), pp. 646-647.