Zinc is named from the German Zink, obscure origin and has been known since prehistoric times. It was not recognized as a distinct element until 1746. The principal ores of zinc are sphalerite or blende (sulfide), smithsonite (carbonate), calamine (silicate) and franklinite (zinc, manganese, iron oxide). Zinc can be obtained by roasting its ores to form the oxide and by reduction of the oxide with coal or carbon, with subsequent distillation of the metal. Zinc is a bluish-white, lustrous metal that is brittle at ordinary temperatures but malleable at 100 to 150 degrees C. and is a fair conductor of electricity. It is widely used to form alloys with other metals. Zinc oxide is a unique and very useful material. It is used in the manufacture of paints, rubber products, cosmetics, pharmaceuticals, floor coverings, plastics, printing inks, soap, storage batteries, textiles, electrical equipment and other products. Zinc is an essential element in the development of human beings and animals.