As colourant in glasses and porcelain enamel glazes http://www.easchem.com/en/products/Erbium+Oxide.html ITEM: Er2O3/TREO(%,min) TREO(%,min) SPECIFICATIONS 99.5 99.0 RE Impurities(%/TREO,Max) CeO2: 0.01 La2O3: 0.01 Pr6O11: 0.01 Nd2O3: 0.01 Sm2O3: 0.01 Eu2O3: 0.01 Gd2O3: 0.01 Tb4O7: 0.01 Dy2O3: 0.01 Ho2O3: 0.01 Tm2O3: 0.01 Yb2O3: 0.01 Lu2O3: 0.02 Y2O3:ã?? 0.01 Non-Re Impurities(%,Max) Fe2O3: 0.001 SiO2:ã?? 0.005 CaO:ã?? 0.01 Cl-:ã?? 0.01 ã?? L.O.I: 0.26%
