Zinc

(Chemical symbol Zn). Element of atomic number 30, atomic weight 65.38, mp 419.58C, specific gravity 7.133. Zinc ores were used for making brass by cementation long before the metal was used in its pure form. The limit of zinc that can enter into solid solution in copper by this process is 28%. The Romans made extensive use of brass and, in India, zinc was being made by distillation in retorts during the 13th century AD. The metal was not known in Europe until rediscovered in 1746. Zinc is a bluish-white, lustrous metal, brittle at ordinary temperatures but malleable at 100 - 150C.