Impedance spectra of a variety of mineral admixtures in dry state as well as in aqueous paste were shown with a view to comparing the difference among them and elucidating the mechanism of their hydration process.It is shown that the impedance of mineral admixture is in the range of dielectrics,however,their Cole-Cole plot is quite different from the ordinary dielectrics.Though there exit the stages of initial and final setting in the hydration process of mineral admixtures,it is far simpler than that of cement.