Fe-rich olenite with tetrahedrally coordinated Fe3+ from Eibenstein, Austria: Structural, chemical, and Mošssbauer data
- Author(s)
- Andreas Ertl, Franz Pertlik, M. Darby Dyar, Stefan Prowatke, John M. Hughes, Thomas Ludwig, Heinz-Jürgen Bernhardt
- Abstract
A sample of dark green Fe-rich (~7 wt% FeOtotal) and Mn-bearing olenite from a beryl-bearing granitic pegmatite near Eibenstein, Lower Austria, was chemically and structurally characterized. Electron-microprobe analyses clearly indicate a deficiency in Si. Tetrahedrally coordinated B was not found by chemical analysis (2.98 apfu B by SIMS analysis) or structure refinement, A Mošssbauer analysis clearly shows that 90% of the total Fe content occurs as [6]Fe2+ at the Y site (~0.8 apfu [6]Fe2+), and 10% occurs as Fe3+ (~0.0 apfu [4]Fe3+) at the T site. The optimized formula, calculated from chemical and structural data, is X(Na0.52Ca0.0 1? 0.47) X(Na0.52Ca 0.01?0.47) Y(Al 1.62Fe2+0.83Mn 2+0.42Li0.05Ti4+0.03?0.05) Z(Al 5.87Mg0 .13) Si5.73Al 0.17Fe3+0.10) O18 (BO 3)3 [(OH)3.32 O0.54F 0.14]. The structure refinement [a 15.938(1), c 7.136(1 A°, R3m] yielded an R value of ~0.022 for 3818 reflections. The observed bond-length is 1.624 A°, in accord with the assigned site-populations: (Si5.73Al0.17Fe 3+0.10). This is the first example of olenite in which tetrahedrally coordinated Fe3+ has been found. The Li content (0.05 apfu), which was determined by SIMS analysis, is uncommonly low for an Al-rich, Mg-poor tourmaline (~0.1 apfu Mg). The O1 site is occupied by [O0.54(OH) 0.32F0.14]. We conclude that the Li content in Al-rich and Mg-poor (natural) tourmaline is very low where the O1 site is occupied mainly by O2-.
- Organisation(s)
- Department of Mineralogy and Crystallography
- External organisation(s)
- Mount Holyoke College, Scientific Software Center, Miami University, Ruhr-Universität Bochum (RUB)
- Journal
- The Canadian Mineralogist
- Volume
- 42
- Pages
- 1057-1063
- No. of pages
- 7
- ISSN
- 0008-4476
- Publication date
- 2004
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 1051 Geology, Mineralogy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/16aecd68-7a6c-4148-b71f-b8cd234f194c