1. Department of Applied Geology, Ruhr University Bochum Institute of Geology Mineralogy and Geophysics, Universitätsstraße 150, Bochum 44780, Germany (Corresponding author), e-mail: sascha.frank@rub.de, http://orcid.org/0000-0001-9421-9860
2. Department of Crystallography, Ruhr University Bochum Institute of Geology Mineralogy and Geophysics, Universitätsstraße 150, Bochum 44780, Germany
3. Department of Particle Technology, Ruhr University Bochum Faculty for Mechanical Engineering, Universitätsstraße 150, Bochum 44801, Germany
4. Department of Applied Geology, Ruhr University Bochum Institute of Geology Mineralogy and Geophysics, Universitätsstraße 150, Bochum 44780, Germany