This paper reports on the acid-promoted dissolution of microporous zincophosphate frameworks of faujasite (ZnPO-X) and sodalite (ZnPO-S) topologies. Elemental analysis of the solution as well as local pH changes around the dissolving crystallites were measured. In addition, diffraction and electron microscopy of the resulting solid that formed on the microporous zincophosphates upon dissolution was examined. It was found that hopeite, Zn-3(PO4)(2), was formed in both cases, though with quite distinct sizes, being of the order of similar to1 mum on ZnPO-X and similar to30 mum on ZnPO-S. The hopeite coating on ZnPO-X was dense as compared to that on ZnPO-S. The local pH change around the dissolving crystal correlated well with hopeite formation. Both elemental analysis and pH measurements indicated that the formation of hopeite was more pronounced on the ZnPO-X. Upon gentle stirring of the medium around the dissolving crystallites, the pH changes around ZnPO-X and ZnPO-S became similar, suggesting similar hopeite formation rates. On the basis of these results, we propose that the nucleation of hopeite occurs on the zincophosphate surface via heterogeneous nucleation, with the nuclei coming from the dissolution products of ZnPO-X and ZnPO-S. Differences in the morphology of the hopeite are ascribed to the differences in dissolution products between ZnPO-X and ZnPO-S. The stronger perturbation of the stirring experiments on hopeite formation from ZnPO-X is interpreted as arising from the smaller size of the dissolution units and, hence, more susceptible to convection effects.