1. Nanomaterials Research Centre, Kola Science Centre, Russian Academy of Sciences, Fersmana 14, 184209 Apatity, Russia
2. Department of Crystallography, Institute of Earth Sciences, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg, Russia
3. Geological Institute, Kola Science Centre, Russian Academy of Sciences, Fersmana 14, 184209 Apatity, Russia