Lorenzenite from the Bratthagen nepheline syenite pegmatites, Lågendalen, Oslo Region, Norway

Lorenzenite, Na 2 Ti 2 Si 2 O 9 , from nepheline syenite pegmatites at Bratthagen, Lagendalen, Vestfold county, Norway occurs in two morphologically different habits: as well-defined orthorhombic crystals or more rarely as fibrous aggregates. Crystal forms observed: {100}, {210}, {111}, {211}, {321}. The unit cell dimensions for Bratthagen lorenzenites are (coarsely crystalline/fibrous): a = 14.488(2)/14.480(1) A, b = 8.7061(11)/8.6995(8) A, c = 5.2308(8)/5.2277(3) A. D meas for coarsely crystalline lorenzenite is 3.436(1) g/cm 3