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Discovery
Indium was discovered in 1863 by the physicist Ferdinand Reich and the chemist Theodor Richter at the Freiberg Mining Academy. They actually wanted to use spectral analysis to detect the recently discovered element thallium in the mineral sphalerite (zinc blende). However, instead of the expected green spectral line of thallium, an indigo blue one appeared. They were unable to assign this to any of the elements commonly used at the time. Indium owes its name to the Latin name for this color: indicum. This in turn goes back to India, from where the dye indigo was exported to Europe for many centuries.
Ferdinand Reich, AI-generated
Hieronymus Theodor Richter, AI-generated
Indium was presented at the World Exhibition in Paris in 1867. An often told but historically unverifiable anecdote says that the public only got to see a lead ingot. Meanwhile, the discoverer Theodor Richter secretly presented a real, specially produced indium bar to a specialist audience.
Extraction
Commercial production of indium began in the 1940s. According to the US Geological Survey (USGS), the United States was the largest producer of refined indium until 1951. Annual production rose from a few hundred kilograms to almost five tons. In the following decades, other countries gained in importance, including South Korea, Japan and Canada, and to a lesser extent France, Germany and Belgium.
Demand and production volumes fluctuated significantly over the years. From the late 1980s, however, an upward trend was observed, driven by growing demand in the display, semiconductor, optoelectronics and alloy sectors. Indium also became increasingly important as a solder material in electronics.
In the 2000s, China greatly expanded its production capacities and is now by far the largest producer, followed by South Korea. The amount of refined indium produced worldwide in 2025 was around 1,000 tons. Then as now, indium is mainly obtained as a by-product of zinc production.
Historical areas of application
Laboratory in the early 20th century, symbolic image
In 1924, it was discovered that indium can stabilize non-ferrous metals such as aluminium or copper in alloys. It found its first concrete application in dental gold in the 1930s. During the Second World War, indium was used as an alloy component to protect heavily stressed aircraft components from damage and corrosion. Other early uses included solders (the raw material is still used for this purpose in specialist areas today) and electronic components such as transistors.
In the 1950s and 1960s, indium was used as an alloy additive in the control rods of nuclear reactors. With the use of indium gallium nitride (InGaN) in green and blue LEDs in the early 1990s, a use that is still relevant today was added. However, the most important commercial application is indium tin oxide (ITO), which has also been widely used in LCD displays, touchscreens and flat screens since the 1990s.