(color online) Calculated diffusion coefficients of dry K-feldspar single crystal by using the Nernst–Einstein equation at 2.0 GPa, and their comparison with previous studies. Black solid lines represent the results of this work; pink dotted line represents the self-diffusion coefficient of sodium in natural single-crystal alkali sanidine with a chemical composition of at room pressure from Wilangowski et al.;^[66] blue dashed line represents the calculated average diffusion coefficient of potassium ions in polycrystalline K-feldspar aggregate along different orientations at 2.0 GPa from Hu et al.;^[30] green dashed line represents the potassium diffusion coefficient of orthoclase glass at room pressure from Jambon and Carron;^[73] red dotteded and dash lines represent the self-diffusion coefficients of potassium and sodium ions for the natural orthoclase ( ) at 0.2 GPa from Foland,^[72] respectively; purple dotted line represents the K self-diffusion coefficient for pure microcline perthite ( ) at room pressure from Lin and Yund.^[71]