The effects of composition and temperature on the partitioning behavior of Sc, Ni, V, U and Th, and the high field strength elements (HFSE) Zr, Nb, Ta and Hf between magnetite and natural silicate melts were evaluated from doped experiments on natural mafic- to intermediate-composition lavas at 1-atm pressure. Composition was found to be the strongest controlling factor on partitioning behavior. The partition coefficients (D) for Zr, Nb, Hf and Ta correlate with D T i and are similar to one another for any given magnetite-melt pair, but vary from < 0.02 in Cr-Al-rich magnetites and chromites to < 2 in titanomagnetite. D S c is higher than D Z r ,D N b , D H f and D T a , and also correlated to D T i . In contrast, Ni is more compatible in Al-Cr-rich magnetites than in titanomagnetites, but is compatible in all magnetite-melt pairs in our experiments. V is generally more compatible than Zr, Nb, Ta and Hf, but its behavior is complicated by its multiple valence states. U and Th are incompatible (D < 0.035) in all magnetites. Expressions were derived to describe the relationship between D and the most strongly correlated parameters, oxide Fe/Mg ratio and Al, and D T i . These patterns of behavior are consistent with the observed miscibility gap between the spinel-group end-members.Equilibrium constants for spinel end-member-melt reactions were parameterized in terms of temperature, pressure and composition. These expressions can be used to predict the temperature and composition of equilibrium spinels. These major-element constraints can also be used to predict spinel-melt partition coefficients using the expressions describing D H F S E as a function of D T i and composition.