Synthesis of monoclinic celsian barium aluminosilicate by a three-step firing technique with or without the addition of Li2O was studied using X-ray powder diffraction (XRD). Prefiring BaCO3 and SiO2 at 1150 degreesC to yield BaSi2O5 prevents the reaction path to hexacelsian via the formation of BaAl2O4. Reacting BaSi2O8 with Al2O3 at 1200 degreesC to yield hexacelsian BaAl2Si2O5 (BAS) would encourages the formation of monoclinic celsian nucleus. Finally, the ground hexacelsian powder is annealed at temperatures between 1200 and 1530 degreesC to promote the transformation of hexacelsian-to-celsian. With the presence of 0.4 wt. % Li2O, complete transformation to celsian occurs at temperature as low as 900 degreesC in 4h.