I have compiled a list of sources for the elements that are available to the amateur chemist. Holmium will be discussed here.
Holmium is one of the less reactive rare earth metals. It forms a yellow trivalent solution when dissolved in acids. Holmium(III) oxide has a color that changes depending on the light source. In normal light it is a dull yellow, while in trichromatic light it is bright pink.
In element form: No sources found.
In compound form: Commercial calibrators for spectrophotometers use holmium oxide glass or in some cases a holmium oxide solution.
I do not have any holmium or holmium compounds at the time of this writing.