Erbium color characteristics

Marignac investigated erbium precipitates and found that they were not homogeneous. Two elements were present. One formed red salts with a characteristic absorption spectrum, while compounds of the other element were colorless. The element with the red color kept the name erbium, the other he called ytterbium. The discovery was made in 1878 and separation was possible by addition of hyposulfurous acid to chloride solutions. The erbium precipitated but not the ytterbium. The two elements erbium and ytterbium also appeared to be mixed, and research had to continue. 

Erbium has a limited use. It is, however, possible to exploit the fact that, like many lanthanides, the element has specific light absorption characteristics. Erbium oxide, itself rose pink, colors glass and glazing. This glass absorbs infrared radiation. 

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