Apparatus and process for separating particles of wollastonite ore and other aspect ratio materials into a relatively high aspect ratio constituent and a relatively low aspect ratio constituent includes an initial step of either size reducing (2) the material into particles of the aspect ratio material having a size less than a preselected maximum size or alternatively providing such particles of the aspect ratio material. The particles of the aspect ratio material are then separated (4) into a plurality of particle streams based on particle size such that each particle stream is formed substantially from particles within a particular range of particle sizes. Then, the particles in at least one particle stream are sorted (6) based on particle shape into the relatively high and relatively low aspect ratio constituents. The particle separation step (4) is preferably performed using mesh screening apparatus. The shape sorting step (6) is preferably performed using apparatus for separating grain.