Nanoparticles in natural systems are comprises of a broad spectrum of mineral and mineraloid species. These materials are often among the most readily-formed solid phases at under surficial and diagenetic conditions, even though at larger crystal sizes these materials may be metastable. This stems largely from the fact that many common nanoparticle phases have lower surface energies than common stable silicate and oxide minerals. In addition, their surface properties of affords them unique abilities to sorb and desorb organic and inorganic species. Recent work has been concentrated on humate and related materials on the surfaces of a several minerals including clay minerals and phosphates. Other aspects of this work include studies of ordered-disordered structures, compositional inhomogeneities , and recrystallization mechanisms. In addition, we have been investigating the fundamental thermodynamic properties of these materials through calorimetric, phase equilibrium, spectroscopic, and theoretical methods in order to develop rigorous quantitative models of their stability and fate in geochemical systems. Of particular interest in this work are zeolites, clays, Fe-Ti oxides, and phosphate minerals. These data are of importance not only for assessing the behavior of these materials in natural systems, but in industrial processes as well. One major thrust of our current research is understanding the behavior of nanophase water included in zeolites, which is an important process in dessication and heat pump technology.