Calcium carbonates are highly important in geochemistry and especially in biomineralization. In nature, organisms can form each of the anhydrous polymorphs selectively for various purposes from precursor amorphous calcium carbonate (ACC). the stability of ACC can be controlled by incorporating various ions such as Mg and Phosphate. The stabilising effect of these ions is generally attributed to their strong interaction with water. By binding water more strongly they should create bottle necks for water diffusion and thereby lower the overall diffusion. This we plan to study using QENS on ACC and it's Mg and Phosphate equivalents as well mixtures of the these three compounds.