Sulphur

Sulphur occurs native most frequently in volcanic regions; or in thick beds associated with gypsum and celestine, as in Sicily; or as a deposition from geysers; or as a sublimate in volcanic craters, as at Kilauea. It crystallises in the Prismatic system in sulphur-yellow, translucent crystals, with resinous lustre, a hardness of 1.5 to 2.5, and a specific gravity of 2. Though much sulphur in commerce is obtained by roasting pyrites, native sulphur is the source of a considerable proportion of that which we use. In medicine sulpbur has been largely employed in the form of unguentum sulphuris in the treatment of certain skin diseases, and particularly with a view to destroying the parasite of Scabies (itch).