More commonly known as washing soda, soda ash is a water-soluble sodium salt of carbonic acid. This white crystalline decahydrate easily efflorescence to form a white powder monohydrate form that is both odorless and has hygroscopic properties. Soda ash is widely used as a domestic water softener, and was historically extracted from the ashes of salt-water plants or plants that grew in sodium rich soil. Today it is industrially produced en masse from salt and limestone using a method called the Solvay process. Soda ash is vital in the production of glass, as it acts for a flux for silica and lowers its melting point without the need for special materials. Soda glass such as this is mildly water soluble, so soda ash and calcium carbonate is added during the melting process to make it completely insoluble. The resulting soda lime glass is the most commonly used household glass manufactured today.