Gold analyses of whole rock, mineral, and groundmass of seven calc-alkalic volcanic rocks (basalt to rhyolite) show that gold is less abundant in the dominant phenocrystic phases than in the whole rock; groundmass concentrations are also lower than whole rock. Crystal-liquid partition coefficients arehornblende, and about 1 for olivine, pyroxene, magnetite, and biotite. If only the principal phases are considered, the bulk gold partition coefficient is typically