were synthesized in a two-step sintering process. Qualitative and quantitative XRD and Rietveld method were applied to control the degree of reaction after each sintering step. Two microscopic techniques for Q-phase crystal habit determination were applied: reflected light microscopy and electron scanning microscopy. Additionally, WDS x-ray microprobe for chemical composition determination of pleochroite crystals was used. A microscopic observation of the polished sections and fractures etched with 10 % HCl and 1 % Borax water solution was carried out. It was observed that Q-phase crystallised in a prism form on the non-etched samples. Lamellar microstructure of prismatic pleochroite crystals on the etched samples was revealed and layers of intergrowths (most probably gehlenite (Ca2Al2SiO7) were observed. The obtained results were discussed on the basis of literature data.