The present invention provides an apparatus for the production of Graphene and similar atomic scale laminar materials by the delamination of a bulk laminar material, such as graphite; the apparatus comprising a pump (112) for pumping a fluid, the fluid being a suspension of solid particles of the bulk laminar material, at a pressure of greater than 1 MPa, along a fluid conduit (12) and against an impact head (16) having an impact face perpendicular or substantially perpendicular to the trajectory of the incoming fluid, being the principal axis relative to the proximal end of the conduit (24) so as to form a narrow and variable gap (20) and where in the impact head is symmetric about a longitudinal axis which is in line with the principal axis and such that the symmetry allows rotation of the head. This apparatus provides prolonged head life and avoids catastrophic head wear in an isolated region. Overall product quality over time is better maintained. Also, the benefit of a self-unblocking delamination apparatus can be achieved whilst maintaining high product quality and consistency. Relatively small variation in gap size being sufficient to avoid blockage, such as occurs by the aggregation of large particles or groups of particles in the high shear gap used for delamination.