Per Teodor Cleve, a Swedish chemist, discovered holmium in 1879. He started by removing all of the known contaminants from erbia, the oxide of erbium, which had been discovered in 1864. After further processing, he obtained two new oxide compounds: one brown, which he named ‘holmia' for the Latin word for the city of Stockholm and the other green which he named ‘thulia'.
Today, holmium is primarily obtained through solvent extraction processing of the Chinese clay deposits. Holmium is relatively soft and malleable, and is stable in dry air at room temperature. It oxidises rapidly in moist air and at elevated temperatures. The metal has unusual magnetic properties.
Applications of Holmium:
- Glass and Ceramics: Holmium is used as a yellow and red glass colouriser. Holmium is also one of the colourants used for cubic zirconia for use in jewellery, providing a dichroic colour in peach or yellow.
- Magnets: Holmium has one of the highest known magnetic moments. It has been used to create the strongest artificially generated magnetic fields when placed within high-strength magnets as a magnetic pole piece or magnetic flux concentrator.
- Electronics and Medicine: Holmium is used in yttrium-iron-garnet and yttrium-lanthanum-fluoride: solid-state lasers found in the microwave equipment used for eye-safe medical and dental technologies. Holmium-containing glass has been used as a calibration standard for ultraviolet and visible light spectro-photometers.
- Energy: Holmium is used in nuclear control rods as it can absorb nuclear fission-bred neutrons.