Note:  Do not rely on this information. It is very old.

Hair Salt

Hair Salt, or Epsomite, is the naturally occuring hydrated sulphate of magnesia, which forms the substance commonly known as Epsom salts (q.v.). It occurs as a fibrous efflorescence at Epsom, Seidlitz, etc., and as fine silky fibres (hence the name) at Idria. The name is also sometimes applied to the naturally occurring sulphate of aluminium or feather alum which occurs in fine fibrous masses in Chili and Bohemia.