... 7minutes ,final setting 15 gypsum powder for cement/chalk: we are the professional manufacture for gypsum powder. we have ourselves gypsum ... fineness of 120 mesh,Initial setting 7 minutes, Final setting for 15 minutes. C) Whiteness is 75% above,the ... hourse),fineness of 250mesh,Initial setting 7 minutes, Final setting for 15 minutes. Useful: cornice, chalk, ceiling, contruction, casting, wall ...