Iridium is so difficult to melt plastic, which greatly limits its practical application. John Isaac Hawkins invented the gold pen with an iridium nib in 1834. In 1880, John Holland and William Loveland Dudley used phosphorus to greatly simplify the melting process of iridium and applied for a patent in the United States. The British company Johnson Matthey later stated that they had been using a similar method to melt iridium as early as 1837, and had exhibited melted iridium at several world fairs.

In 1957, Rudolf Mössbauer discovered that atoms were capable of recoilless gamma-ray resonance emission and absorption in solid metal samples containing only Ir. The experiment he conducted was one of the iconic physics experiments of the 20th century. This phenomenon is called the Mössbauer effect (other nuclei exhibiting this effect have also been discovered one after another, such as Fe), and it is the central principle of Mössbauer spectroscopy and is widely used in physics, chemistry, biochemistry, metallurgy and mineralogy. have important applications. Just three years after the paper was published, in 1961, Mossbauer won the Nobel Prize in Physics for this discovery, at the age of 32.