A materials classifying cyclone with at least one vibrator for transmitting generated vibrations into the downwardly swirling slurry of materials to interrupt the flow pattern thereof so that some of the smaller particles trapped in the outer portions of the slurry are freed for movement into the vortex of the cyclone to increase the operating efficiency of the cyclone. In a first embodiment, the cyclone has a solid metallic conical housing with the vibrator attached to the periphery of the housing. In a second embodiment, a plurality of longitudinal struts in spaced apart relationship provide the conical housing with open sides with the vibrator mounted on one of the struts which transmit the vibrations to abrasion resistant liners mounted in the housing. In still another embodiment, the vibrator is coupled to an abrasion resistant liner which is exposed in one of the open spaces of the conical housing.