Holmium is a lanthanide metal that is a member of the rare earth element group. It has physical and chemical properties that are similar to other rare earth metals, and is a silvery-white metal that is highly reactive with oxygen and water. Holmium is notable for its strong magnetic properties, with a magnetic field strength that is among the highest of any element. This makes it useful in the production of specialized magnets, particularly those used in medical imaging equipment like MRI machines. Holmium is also used in the production of nuclear control rods, which help to regulate the fission reactions that occur in nuclear reactors. In recent years, holmium has also been explored for potential applications in cancer treatment, due to its ability to absorb high levels of radiation.