Seidozerite, a sorosilicate from the seidozerite supergroup (a "titanium disilicate"). It was first described by Semenov, Kazakova and Simonov in 1958.[1] Its chemical formula is Na4MnZr2Ti(Si2O7)2O2F2. Its type locality is pegmatite no. 58, Seidozero lake, Lovozero massif, Kola peninsula.[2]