The name is derived from indigo, because of its blue spectrum. It was discovered in 1863.
Some of its uses: mirrors, photo-effect, transistors, car bearings, and long life batteries. It adheres to glass. It squeaks on being bent. Combined with Arsenicum it becomes a semiconductor (just like Gallium), used in infra red diodes. Alloys of Indium and Germanium are used to make transistors. For soldering of printing plates they add Indium to ensure maximum contact.