The proposed research concerns the role of water and hydroxide in nominally anhydrous materials. The focus of the study will be on determining the "sites" of these hydrous components in the host phase, on correlation of species type and concentration with properties of the host phase, and on elucidating changes in these species among various geologic environments. This will be accomplished through a program of spectroscopic investigations and computer simulations of both natural and laboratory- synthesized silicate and oxide phases. Results of the research should increase our understanding of the manner in which these trace "hydrous" components influence properties such as mechanical strength, optical behavior, dielectric constants, and response to ionizing radiation of the host phase.