Alberti A , Cruciani G , Galli E , Merlino S , Millini R , Quartieri S , Vezzalini G , Zanardi S , Journal of Physical Chemistry , B106 (2002) p.10277-10284, Crystal structure of tetragonal and monoclinic polytypes of tschernichite,, the natural counterpart of synthetic zeolite beta, Locality: Mt. Adamson, Northern Victoria Land, Antarctica, Sample: large crystal, monoclinic