Ais forAlum

Alum could refer to either a specific mineral, or a general class of similar ones. ( /?æl?m/) is both a specific chemical compound and a class of chemical compounds. The mineral usually referred to as alum is hydrated potassium aluminium sulfate. Alum is an effective blood coagulant, and used to be sold in blocks as part of shaving kits. You use it to stop shaving cuts from bleeding.