There are over three thousand different minerals. On the basis of composition, minerals are classified mainly as metallic and non-metallic minerals • Metallic minerals contain metal in raw form. Metals are hard substances that conduct heat and electricity and have a characteristic lustreor shine. Iron ore, bauxite, manganese ore are some examples. Metallic minerals may be ferrous or non-ferrous. Ferrous minerals like iron ore, manganese and chromites contain iron. A non-ferrous mineral does not contain iron but may contain some other metal such as gold, silver, copper or lead. • Non-metallicminerals do not contain metals. Limestone, mica and gypsum are examples of such minerals. The mineral fuels like coal and petroleum are also non-metallic minerals