Six samples of complex composition were synthesized, using as raw materials aluminum, magnesium and titanium oxide and also zirconium silicate. The samples were thermally treated at temperatures in the range 1250-13500C. The sinterability was determined on the thermally treated samples by measuring the shrinkage at firing, water absorption and apparent density. By X-ray diffraction it was found that the two equilibrium components, tialit and mullite, were formed. Besides of these there are unreacted raw materials which show that the reactions totally are not. The texture of the samples examined by electronic microscope was uniform and shows the presence of some grains with a predominantly prismatic shape and with dimensions less than 5 μm.