Characteristics: Elemental holmium is a crystalline rare earth element, relatively soft and malleable with a silvery-white metallic luster. Soluble in dilute acids. It is too reactive to be found uncombined in nature, but when isolated, is relatively stable in dry air at room temperature. However, it reacts slowly with water and rusts readily, and will also burn in air when heated. Holmium has the highest magnetic strength (10.6 µB) of any element and therefore is used for the pole-pieces of the strongest static magnets, as well as other magnetic properties: when combined with yttrium, it forms highly magnetic compounds, is paramagnetic at ambient conditions and ferromagnetic at temperatures below 19 K
Derivation: Holmium is found in the minerals monazite and gadolinite, and is usually commercially extracted from monazite using ion exchange techniques, but is still difficult to separate from other rare earths.
Holmium has the highest magnetic strength of any element and is used to create the strongest artificially generated magnetic fields. Since it can absorb nuclear fission-bred neutrons, it is also used as a burnable poison to regulate nuclear reactors. For medical applications, holmium is used in yttrium based solid-state lasers found in microwave equipment which in turn finds it’s way into medical and dental practice.
Holmium is also a colorant used for cubic zirconia and glass by yielding a yellow or red coloring. Glass containing holmium oxide and holmium oxide solutions are used as a calibration standard for optical spectrophotometers.
Hazards: Holmium has a low level of acute toxicity, however, large amounts of holmium salts can cause severe damage if inhaled, consumed orally, or injected. The biological effects of holmium over a long period of time are not known.