The emphasis of this exploratory project is to conduct an experimental study of the partitioning of boron between muscovite and aqueous fluids. The experiments will involve the use of double-capsule techniques, with the run products being analyzed by isotope dilution. Run conditions for the study are 600, 800, and 1000oC at 2 GPa and at 800oC at 1,2 and 3 GPa. The techniques developed in this research and the partitioning results will ultimately find application in research related to the use of boron and its isotopes as geochemical tracers in subduction zone processes.