Holmium was discovered by Cleve in 1879 and named for the Latinized version of the name for Stockholm. Like most of the other rare-earth metals, it is silvery and soft, and can be pounded or rolled into very thin sheets. At normal temperatures it is fairly inert but will oxidize at high temperatures and humidities.
Like most of the rare-earth metals, holmium is generally obtained from monazite sand, where it is present to the extent of about 0.05%. Most holmium use is confined to research.
Stephen R. Marsden (ChemTopics)