iPhone problem with .mov files

Has anyone had this problem? I received a movie file of type .mov on my iPhone 4s as an attachment in e-mail. It was made on another iPhone 4s but I can't get it to play or move it to my camera roll. When i click on it it shows a black screen that says "loading..." for about 1 second and then goes back to the e-mail view that I clicked on. Since it was made and came from another iPhone 4s it should be in the proper .mov format.