Holmium is a metallic chemical element grouped with the lanthanides in the periodic table of elements. This group of elements are also known as rare earth elements; they share an assortment of qualities which are useful in a wide range of industries. This particular lanthanide has few uses, and consumers rarely interact with it, although they may in some cases own products which are made with the assistance of holmium. It should be noted that, like other “rare” earths, holmium is in fact not at all rare; the world's primary source of holmium is China, where it is actually relatively abundant.
This element rarely appears in nature in a pure form. It is typically found in minerals such as monazite and gadolinite. When isolated, holmium is a silvery white, relatively soft metal which usually remains stable at or around room temperature. However, when heated in moist conditions, the element will oxidize, and it can react adversely with other metals. On the periodic table of elements, holmium is identified with the symbol Ho, and it has an atomic number of 67.
Credit for the discovery of holmium is usually given to Marc Delafontaine and Jacques-Louis Soret, two Swiss chemists who discovered the element with the assistance of spectroscopic observation in 1878. In the same year, Per Teoder Cleve also discovered the element, and named it after the Latin name for his native city of Stockholm. Like other lanthanides, the element proved challenging to isolate, and reliable methods for isolation were not developed until the mid-1900s.
Holmium does not have very many uses. Like other rare earths, it is used as a dopant in lasers, and it is sometimes alloyed with other metals to create magnets. Holmium is actually strongly magnetic, and it is sometimes used in experiments which require an intense magnetic field. The metal is also used in nuclear research, and as a coloring agent for yellow glass. It may also sometimes be used to color cubic zirconium for the purpose of making yellow gemstones.
The toxicity of holmium is not known. It is probably at least mildly toxic, as many rare earth metals are, and it should be handled carefully as it can be reactive. As a matter of common sense, people should wear gloves and face protection when handling this element, especially if they plan to heat it, thereby releasing fumes. The element does not appear to play a role in the human body, even in trace amounts.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.