The cocrystallization of erionite during the synthesis of tetramethylammonium-offretite produces faults in the crystalline structure known as stacking faults. The presence of such stacking faults is studied as a function of the amount of tetramethylammonium (TMA) bromide template added. Simultaneously the effect of the stacking faults on the shape selectivity of toluene disproportionation is also studied. Characterization of the catalytic material is carried out by XRD, SEM, and toluene disproportionation used as the test reaction.