Sulfur is named from the Latin sulphurium, and has been known since ancient times. It is referred to as brimstone in the bible book Genesis. Sulfur occurs native near volcanoes and hot springs. It is widely distributed in nature as iron pyrites, galena, sphalerite, cinnabar, stibnite, gypsum, Epsom salts, celestite and barite. Sulfur is commercially recovered from wells sunk into the salt domes along the Gulf Coast of the U.S. Sulfur also occurs in natural gas and petroleum crudes and must be removed from these products. Sulfur is a component of black gunpowder and is used in the vulcanization of natural rubber and as a fungicide. A tremendous tonnage is used to make sulfuric acid, the most important use. It is also used in making sulfite papers and other papers, as a fumigant and in the bleaching of dried fruits. Sulfur is essential to life as it is a minor constituent of fats, body fluids and skeletal minerals.