Ertl A , Rossman G R , Hughes J M , Prowatke S , Ludwig T , American Mineralogist , 90 (2005) p.481-487, Mn-bearing oxy-rossmanite with tetrahedrally-coordinated Al and B from, Austria: Structure, chemistry, and infrared and optical spectroscopic study, Sample: REDT4 from Eibenstein an der Thaya, Lower Austria, Reported formula: (Na.46 Ca.01) (Al2.35 Li.32 Mn2+.28 Fe2+.04 Ti4+.01) Al6, (Si5.51 Al.25 B.24) O18 (BO3)3 [(OH)2.80 O.20] [O.86 (OH).10 F.04], Tourmaline