I have compiled a list of sources for the elements that are available to the amateur chemist. Germanium will be discussed here.
Germanium is a hard, inert, and brittle metalloid from Group 14 on the periodic table. Germanium has properties intermediate between tin and silicon. In the early days of electronics, germanium was the primary semiconducting material because purity is not essential for it to work. Silicon, because of its great abundance, has since superseded germanium in almost all electronics applications. Germanium forms quadrivalent covalent compounds with very low boiling points. Germanium can be used as a nutritional supplement but this use is questionable. Germanium dioxide is a white amphoteric solid that can dissolve in both acids and bases.
In element form: Germanium windows were used for motion sensors in the past. Germanium diodes are still found in old electronics equipment.
In compound form: Germanium compounds are used in the phosphors for mercury vapor lamps. Germanium dioxide is used in fiber optic cables.
Here is my sample of germanium, small germanium crystals from old diodes.