Thin films having ZnO nanocrystallites, with a minimum average size of 2.2 nm, embedded in an amorphous gold oxide matrix have been investigated. These structures do not present a blue-shift of the absorption spectra relative to those corresponding to large ZnO crystallites, a shift which would be expectable for this range of particle size. It was found that the hydrated gold oxide has a much narrower energy gap than ZnO and does not creates quantum wells in the ZnO crystallite region. The Raman spectra present only the confined vibration modes of ZnO. These peculiarities of the mixed system were analyzed by means of an adequate energy band diagram. A Raman resonant effect, determined by interface transitions, has also been detected.