Electromagnetic emission (EME) caused by fracturing of piezoelectric effects in rocks has been studied. We have analyzed a finite size piezocrystal undergoing such mechanical stresses which cause an uniform movement of a crack. Direction of the crack movement and its front orientation have been assumed arbitrary with respect to the crystal axes. In such a case polarization currents appear with potential and vortical components, corresponding to the electric polarization currents and magnetization currents. Amplitude-frequency characteristics of the EME in long-wavelength region have been analyzed too. This effect of EME is of great importance for natural hazards including volcano eruptions and earthquakes.