AM_Roumaite Formula: Ca3.19 Na2.07 Ce1.22 (Nb.55 Ti.45) Si4 O15 (F3 H) Name: Roumaite Unit cell: 7.473 11.294 18.778 90.0 101.6 90.0 , V=1552.49 Space group: C1C1 (9)

Biagioni C , Bonaccorsi E , Merlino S , Parodi G C , Perchiazzi N , Chevrier V , Bersani D , The Canadian Mineralogist , 48 (2010) p.17-28, Roumaite, (Ca,Na)3(Ca,REE,Na)4(Nb,Ti)[Si2O7]2(OH)F3, from Rouma Island,, Los Archipelago, Guinea: A new mineral species related to dovyrenite, Locality: Rouma Island, Los Archipelago, Guinea