Abstract: Apparatus for crushing rock, stone and like material is described. The apparatus includes primary and secondary crushing chambers containing respectively a rotary impactor and a hammer mill. The apparatus can operate either in a wet mode or in a dry mode. In the former case material is processed successively in the two crushing chambers and discharged from the apparatus. In the wet mode, material is first processed in the primary crushing chamber and then discharged from said chamber for processing externally of the apparatus. At least some of the material is then returned to the secondary crushing chamber for further processing and discharge.