Reactions at the surface of minerals are extremely complex and span an enormous range of time scales. However, by modeling the mineral surface using structurally similar metal (hydr)oxide nano-size clusters, we can better understand the reactivity at specific sites on a mineral surface. Our research efforts attempt to examine the oxygen exchange rate of different oxygen functional groups from small rhodium nanoclusters, both in solution and in the solid phase. By using rhodium clusters, the oxygen exchange rate is slow enough to measured using O-17 NMR spectroscopy, unlike aluminum (hydr)oxide clusters. The oxygen exchange kinetics allows us to derive rate laws for these reactions in order to ultimately predict the mechanism of mineral growth and dissolution. Understanding the reactivity of mineral phases is important in that mineral oxides degrade and/or consume toxins such as pesticides, heavy metals and hydrocarbons that are damaging to the environment.