Based on the experimental study, the formation mechanism of radial fissures and small holes in quartz grains from active fault gouges is dealt with in this paper. A new standpoint, of which the radial fissures and small holes result from the explosion of inclusions in the quartz grains in the course of stick slip friction of the active faults, is put forward. The conclusion is that radial fissures and small holes in quartz grains can be regarded as a new mark identifying stick slip of active faults.