<p>In this second article dedicated to the structural analysis of twins in feldspars, we present the results for albite and pericline twins in alkali triclinic feldspars. The strong monoclinic structural pseudo-symmetry and orthorhombic metric pseudo-symmetry of the lattice are considered the rationale for the occurrence of both albite and pericline as growth twins. However, these pseudo-symmetries are less marked for triclinic albite than for microcline. This results in a stronger distortion of the coordination polyhedra at the composition plane for pericline twins, whose occurrence should therefore be less probable than in microcline. The old hypothesis that pericline twinning should be only possible as growth twin when the rhombic section approaches the (001) pinacoid, i.e. in plagioclases, seems contradicted by the computed atomic structure at the composition plane. The structure is less distorted in the case of microcline, i.e. when the rhombic section approaches the (200) pinacoid, making pericline twinning more probable as growth twin in microcline.</p>