Twinning in k-feldspars from the interplay between the ionic and electronic lattices

Ordinary and diagonal Albite and Pericline twins are studied in a transitional microstructure from orthoclase-microcline recrystallization in the K-feldspars of the Fermin pegmatite (MG, Brazil) using polarized light microscopy (PLM), Raman microprobe (RMP) spectroscopy, scanning and transmission electron microscopies (SEM and TEM). Our data suggest that twin patterns obey to a fundamental behaviour of crystalline matter in which large volumes can act cooperatively as a whole in order to decrease the lattice elastic strain throughout “long-range” interactions. It is proposed that this essential information is propagated via the electronic lattice or a network system formed by the bonding electrons. Twin-structures result from correlations between many distant interacting variants. Changes in the symmetry of the sensitive electron lattice promote subsequent local atomic readjustments in the ionic lattice.