Can a veneer be placed over zirconium crown?

A front tooth on my new bridge is noticeably darker than the adjacent one. I notice it in all natural lighting situations & its very disturbing to me! My smile was supposed to light & shiny, now there is this grayish flaw in the "paint" finish. Its not the post showing through. Its obvious the lab tech did not lay on enough of a coat in the area. This wasn't noticed under dental office fluorescents. I am sick over it!