In 1863, when German chemists Reich and Richter were studying sphalerite, they used a spectrometer to analyze a solution containing zinc oxide and discovered a new blue spectral line. Subsequently, a new metallic element was isolated. So it was named "indium" (indium) by the color of the spectral line. In Latin, indium, that is, indium, means blue. Indium is a silvery white metal with a melting point of only 156.4°C. It is very soft and can be scratched with fingernails and pressed into very thin sheets.

Pure indium is usually only used as an alloying element. For example, indium can be used as an additive to silver-lead alloys for aircraft engine bearings. Artificial prostheses and jewelry are often made from indium and alloys of gold, silver, palladium, and copper. Indium is also included in semiconductor materials, for example, in the production of germanium pnp transistors, indium is often used as an alloying element. Indium compounds such as indium antimonide can be used as materials for infrared detectors, and indium phosphide as materials for microwave generators.