Original paper
Modularity of crystal structures: a unifying model for the biopyribole–palysepiole series
Nespolo, Massimo; Bouznari, Kenza
European Journal of Mineralogy Volume 29 Number 3 (2017), p. 369 - 383
published: Jul 12, 2017
Abstract
Biopyriboles and palysepioles are two polysomatic series traditionally described as built by the juxtaposition of modules taken, respectively, from phyllosilicates and pyroxenes and from palygorskite and sepiolite. We show that all the minerals in these two series can be described in the framework of the tropochemical cell-twinning model as built by modules of variable width taken from phyllosilicates, stacked by different structure-building operations. We present a quantitative comparison of the modules occurring in the different minerals and show their structure is so closely similar that one can use the module taken from one mineral to model the structure of the other minerals with only minimal deformations.
Keywords
modular crystal structures • biopyriboles • tropochemical cell-twinning • pseudo-symmetry • modularity • palysepioles