Crystal morphologies with well-defined macroscopic cavities are very rare occurrences. Tabular crystals of SAPO-40 with a symmetrical notch at each end have been obtained by selective inhibition of the growth of the large-pore faces. Crystal growth has continued on the small-pores (0 1 0) faces, circumvented the inhibited sphenoidal faces formed a protruding tab at the corners of the crystals. (C) 2003 Elsevier B.V. All rights reserved.