Stishovite synthesized from natural basalt showed the highest concentration of hydrogen ever reported. The water concentration obtained from the polished single crystal of stishovite in this study was up to a maximum of 5628 ¿ 291 atoms of hydrogen per 106 silicon atoms (844 ¿ 44 ppm water). The concentration of hydrogen increased with increasing substitution of trivalent cations, which is almost aluminum, and temperature has a significant effect on the incorporation of hydrogen into stishovite. The result of this study suggests that stishovite in subducted basaltic crust could be an important water-containing phase and contribute to the transport of hydrogen to the lower mantle.