|Erbium was found in black mineral from quarry at Ytterby. In 1843 Mosander separated "yttria" from the mineral gadolinite into three fractions which he called yttria, erbia, and terbia.|
However only after 36 years an individual oxide had been extracted from erbia earth. The new element was named after Ytterby, a town in Sweden with separated syllables.
|Lanthanide erbium crustal abundance is 3.3x10-4 mass %, in sea water 6x10-7 mg/L. Erbium has been found in certain titanium minerals and is one of the least abundant of the rare earth elements. As other rare earth elements it is contained in many minerals, including gadolinite, xenotime, euxenite, monazite, bastnasite, loparite and others.|