In 1803 iridium was discovered in London by Smithson Tennant together with osmium.
Both metals were found in black residues after dissolving crude platinum with aqua regia. Iridium owes its name to its variety of colours. Due to its great hardness and brittleness, iridium is very difficult to process. Metals that lack hardness and brittleness are often alloyed with iridium. In addition to alloys for mechanical engineering, medicine and for precision measurements, it is also used in alloys for the jewellery industry. Jewellery pieces that are exposed to high stresses are made in a platinum-iridium alloy. (mechanisms and springs, wedding rings)