Indium is a chemical element wi seembol In an atomic nummer 49. This rare, very saft, malleable an easily fusiblepuirhivy metal is chemically seemilar tae gallium an thallium, an shaws intermediate properties atween thir twa. Indium wis discovered in 1863 an named for the indigo blue line in its spectrum that wis the first indication o its existence in zinc ores, as a new an unkent element. The metal wis first isolatit in the follaein year. Zinc ores continue tae be the primary soorce o indium, whaur it is foond in compoond form. Very rarely the element can be foond as grains o native (free) metal, but thir are nae o commercial importance.