Erbium was discovered in a small town is Sweden called Ytterby. Erbium is found in the minerals under dysprosium. Erbium is obtained by separating yttria, found in the mineral gadolinite, into three parts.
Erbium is one of the three parts.
Erbium is extracted by using a sulfuric acid treatment. It is refined by using pure salts by fractional crystallization and ion exchange. It is also used by turning Erbium into an oxide which is used in ceramics. It is 43rd in abundance of elements found in the Earth's crust. Erbium is in the Lanthanide group.