I have compiled a list of sources for the elements that are available to the amateur chemist. Erbium will be discussed here.
Erbium is a typical not-so-reactive rare earth metal. Erbium forms pink compounds that fluoresce in UV light. It is solely trivalent. These heavy rare earth metals are quite boring as they are so similar to each other.
In element form: No sources found.
In compound form: Some glass is colored pink by the addition of erbium oxide.
I do not have any erbium at the time of this writing.