Abstract: The present invention relates to a process for making a crystalline metallosilicate composition comprising crystallites having an inner part (the core) and an outer part (the outer layer or shell) such that: the ratio Si/metal is higher in the outer part than in the inner part, the crystallites have a continuous distribution of metal and silicon over the crystalline cross-section, said process comprising: a) providing an aqueous medium comprising OH— anions and a metal source, b) providing an aqueous medium comprising an inorganic source of silicon and optionally a templating agent, c) optionally providing a non aqueous liquid medium comprising optionally an organic source of silica, d) mixing the medium a), b) and the optional c) at conditions effective to crystallyze the desired metallosilicate, e) recovering the desired metallosilicate, wherein in the mixture a)+b)+c), before crystallization, the ratio Si org/Si inorganic is <0.3, advantageously <0.