Translation induced by the field-gradient force is being observed for a single ferromagnetic iron grain and a ferrimagnetic grain of a ferrite sample (CuFe₂O₄). From measurements on the translation, precise saturated magnetization of M_S is possible for a single grain. The method is based on the energy conservation rule assumed for the grain during its translation and the grain is translated through a diffuse area under microgravity conditions. The results of the two materials indicate that a field-induced translation of grain bearing spontaneous moment is generally determined by a field-induced potential -mM_SH(x) where m denotes the mass of sample. According to the above translations, the detection of MS is not interfered by any signals from the sample holder. The M_S measurement does not require m value. By observing translations resulting from fieldinduced volume forces, the magnetization of a single grain is measurable irrespective of its size; the principle is also applicable to measuring susceptibility of diamagnetic and paramagnetic materials.