Abstract: An improved centrifugal impactor for crushing rocks includes a hollow housing having a peripheral crushing chamber and a rotor mounted in the housing for rotation relative thereto about a generally vertical axis and spaced radially inwardly from the crushing chamber so as to define an annular passage for communicating a flow of rocks from an upper inlet opening and the crushing chamber to a lower outlet opening. The rotor includes a horizontal platform and a pair of outer and inner annular vertical barrier members attached to and extending upwardly from the horizontal platform. The outer barrier member is disposed about a peripheral edge of the horizontal platform.