Erbium

A rare earth element of the lanthanide series associated with several other rare elements in the mineral gadolinite from Ytterby in Sweden Symbol Er It has atomic number 68 and an atomic weight of 16726 The pure element is metallic with a bright silvery luster It is relatively stable in air not oxidizing as quickly as some other rare earths Its salts are rose colored and give characteristic spectra and the pink oxide has been added as a colorant in glass and porcelain enamel glazes Its sesquioxide Er2O3 is called erbia