“…Gadolinite-datolite-type compounds attract interest because of their physical and chemical properties. They are considered as potential optical materials (Verstegen et al, 1972;Wang et al, 2009;Juwhari & White, 2012;Peng et al, 2016), materials for electrical engineering (Konerskaya et al, 1988;Tummala, 1991;Podlesov et al, 1992;Jean et al, 2002;Liu et al, 2007;Chiang et al, 2008), membrane technology (Farsiyants et al, 1989;Schubert, 2003), protection from neutron radiation (Tarasevich et al, 1990;Mann & Sidhu, 2012) and as a matrix for the immobilization of nuclear wastes (Ojovan & Lee, 2005;Malczewski & Dziurowicz, 2015). In geological sciences, gadolinite group minerals are used as a geochemical marker of magmatic as well as low-temperature processes (Bellatrecia et al, 2006;Zaccarini et al, 2008;Lyalina et al, 2014;Karas' & Ratkin, 2014).…”