Sur la morphologie de quelques cristaux à structure pseudosymétrique

A study of the morphology of chalcopyrite, stannite, wulfenite and manganite shows that the existence of a structural pseudo-symmetry has an influence on the relative importance of the different forms in these crystals. In particular, the reticular planes possessing, in relation to the pseudo-symmetry, a spacing which is a submultiple of the true spacing correspond to forms whose development is in general less common than that predicted by the law of Donnay & Harker.