Fontan, F.Roda, E.2017-01-242017-01-241996http://hdl.handle.net/10272/13151A cruciform intergrowth in a phosphate of the frondelite-rockbrid geite series associated with beryl-columbite pegmatites is studied on the basis of geometric considerations. The crystallographical calculations prove, for the first time, the existence of a reticular pseudomeroedric twinning in frondelite, having as twin plane the (041), an obliquity of ~ 3 and a twin index ~ 7, which may explain the rarity of this twinningspaAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/FrondeliteRockbridgeiteTwinReticular pseudo-merohedriSmjournal articleopen access