Frequency dependence of ac conductivity from 20Hz to 10MHz and time series of the conductivity at 2kHz along c-axis of gadolinium nitrate crystal Gd(NO3)36H2O were measured in the temperature range from 210K to 290K. Meta-stable phenomena were observed. Dynamical property given by the frequency dependence of the conductivity is compared to those in disorder system. Non-periodic instability (burst) was found in the time series data of the conductivity. The frequency dependence of the power spectrum densities is well represented by the power law 1/f α . The exponent α is discussed with the nonlinear dynamical property.