Alum (Potassium alum) is a natural aftershave which contains 100% mineral salts with healing and antiseptic properties. Very popular after-shave treatment as a natural deodorant and a facial toner for oily skin and acne. It is a crystal-like stone that is moistened with cold water and gently rubbed over the entire face to act as an antiseptic for razor burn. It can also help to stop bleeding of nicks and cuts. The Alum block also has antiseptic properties that not only cool and refresh the skin after shaving, but also act as a balm.