Indium is a chemical element with the symbol In and atomic number 49. Indium is the softest metal that is not an alkali metal. It is a silvery-white metal that resembles tin in appearance. It is a post-transition metal that makes up 0.21 parts per million of the Earth's crust.

Where was indium discovered?

Indium was discovered in 1863 by Ferdinand Reich at the Freiberg School of Mines in Germany. Reich was investigating a sample of the mineral zinc blende (now known as sphalerite, ZnS) which he believed might contain the recently discovered element thallium.

How was indium discovered?

Indium was discovered by the German chemists Ferdinand Reich and Hieronymus Theodor Richter in 1863. Reich and Richter had been looking for traces of the element thallium in samples of zinc ores. A brilliant indigo line in the sample's spectrum revealed the existence of indium.