with additional data on each sample including locality, general appearance and mineral association. In...octahedra (M-octahedra) by additional D-octahedra with lower-force characteristics (D ¼ Fe, Mg, Mn or Zn) in...points in Fig. 1.8 is due mainly to the presence of lower-force-strength cations (Ca and Na) in the D site...(Specord 75 IR or Specord M80, Carl Zeiss, Jena, Germany), Perkin Elmer 1600 Series FT IR spectrometer or...FT IR spectrometer (Bruker Optics, Ettlingen, Germany). IR spectrum of a pure KBr disc was subtracted |