The present disclosure relates to crystalline forms and amorphous form of Rosuvastatin Acetonide Calcium which is known by chemical name (3R,5S,6E)- 7 - [4- (4-Fluoro- phenyl) -6-isopropyl-2-(methanesulfony l- methyl-amino ) - pyrimidin-5-yl) vinyl)-2,2-dimethyl-1,3-dioxan-4-yl) acetic acid calcium salt. The disclosure also provides a process for obtaining the same.