Tschörtnerite, a copper-bearing zeolite from Bellberg volcano, Eifel, Germany
- Autor(en)
- Herta Silvia Effenberger, Gerald Giester, Werner Krause, Heinz-Jürgen Bernhardt
- Abstrakt
The new mineral tschortnerite, ideally Ca4(K,Ca,Sr,Ba)3Cu3(OH)8[Al12Si12O48]×xH2O, x ³ 20, occurs as well-formed cubes up to a max. size of 0.15 mm in a Ca-rich xenolith at the Bellberg volcano near Mayen, Eifel, Germany. The light blue, transparent crystals are optically isotropic, n = 1.504(2). Microprobe anal. (in wt. percent) gave CaO 13.10, CuO 9.64, SrO 4.49, BaO 1.93 K2O 1.37, Fe2O3 0.30, Al2O3 25.21, SiO2 30.25, H2O (calc. by difference) 13.71. The empirical formula based on 48 O atoms within the tetrahedral net is Ca5.60Sr1.04K0.70Ba0.30Cu2.90Fe0.09Al11.85Si12.06O48(OH)8.44×14.01H2O. Tschortnerite is cubic, space group Fm.hivin.3m [a = 31.62(1) .ANG., V = 31614 .ANG.3, Z = 16]. The d. is Dmeas = 2.1 g/cm3, Dcalc = 2.10 g/cm3. Single-crystal X-ray investigations showed that tschortnerite is a zeolite; the structure contains interconnection of double six-rings, double eight-rings, sodalite cages, truncated cubo-octahedra, and previously unknown 96-membered cages (tschortnerite cage). A new structural unit is the [Cu12(OH)24]Ca8O24(H2O)8 cluster centered within the truncated cubo-octahedron. The cluster is formed by a rhomb-dodecahedron-like arrangement of corner connected CuO4 squares, the eight CaO7 polyhedra are branched. The sodalite cage houses Ca4(OH)4O12 clusters of edge-sharing CaO6 octahedra. Half-occupied (K,Ca,Sr,Ba) positions were located in the basal and top face of the double eight-rings, i.e., the border to the tschortnerite cage. Within the large tschortnerite cage only H2O mols. were localized.
- Organisation(en)
- Institut für Mineralogie und Kristallographie
- Externe Organisation(en)
- Ruhr-Universität Bochum (RUB)
- Journal
- The American mineralogist
- Band
- 83
- Seiten
- 607-617
- Anzahl der Seiten
- 11
- ISSN
- 0003-004X
- DOI
- https://doi.org/10.2138/am-1998-5-620
- Publikationsdatum
- 06-1998
- Peer-reviewed
- Ja
- ÖFOS 2012
- 105113 Kristallographie, 105116 Mineralogie
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/tschoertnerite-a-copperbearing-zeolite-from-bellberg-volcano-eifel-germany(e4ae3959-e036-4b38-a584-3243a2b19125).html