Holmium oxide, also known as the holmium oxide, the chemical formula Ho2O3, is a compound with oxygen elements holmium rare earth elements, and one of dysprosium oxide and the strongest material known paramagnetic. Holmium oxide, erbium oxide is a component of the mineral. Natural state, holmium oxide often trivalent lanthanide oxides coexist, requiring specialized methods to be separated. Holmium oxide can be used to prepare a special color in the glass. Visible absorption spectrum containing holmium oxide glass and the solution has a series of sharp peaks, so traditionally used spectrophotometer calibration standard. For the manufacture of the new light source lamp dysprosium, holmium, yttrium iron can be used as eligible for yttrium aluminum garnet additives and preparation of metal holmium. Holmium oxide glass is used as the Soviet diamond and yellow, red colorant. Holmium oxide and holmium oxide glass solution (often perchloric acid solution as) spectrum in the 200-900nm range have sharp absorption peaks, and therefore can be used as the spectrometer calibration standard, and has commercialized contain. Like other rare earth elements like holmium oxide it can be used as special catalyst, phosphor, and a laser material. Holmium laser wavelength of about 2.08 μm, can also be a continuous light pulse. This laser eye harmless, can be used in medical, optical radar, wind speed measurements and atmospheric monitoring.