In this study, the volumetric compression of jadeite (NaAlSi2O6) melt at high pressures was determined by three-dimensional volume imaging using the synchrotron-based X-ray microtomography technique in a rotation-anvil device. Combined with the sample mass, measured using a high-precision analytical balance prior to the high-pressure experiment, the density of jadeite melt was obtained at high pressures and high temperatures up to 4.8 GPa and 1955 K. The density data were fitted to a third-order Birch-Murnaghan equation of state, resulting in a best-fit isothermal bulk modulus K T 0 of 10.8 − 5.3 + 1.9 GPa and its pressure derivative K T 0 ′ of 3.4 − 0.4 + 6.6 . Comparison with data for silicate melts of various compositions from the literature shows that alkali-rich, polymerized melts are generally more compressible than alkali-poor, depolymerized ones. The high compressibility of jadeite melt at high pressures implies that polymerized sodium aluminosilicate melts, if generated by low-degree partial melting of mantle peridotite at ~250−400 km depth in the deep upper mantle, are likely denser than surrounding mantle materials, and thus gravitationally stable.