The morphological, mineralogical and chemical evolution of titanite in weathered nepheline syenite is presented here. Weathering begins at mineral boundaries and along intramineral microcracks with initial loss of SiO and CaO. In this process, TiO2 and Fe2O3 become relatively more concentrated as eventually do Zr2O5 and Nb2O5 also. The principal secondary minerais formed are anatase and goethite
