germanium - a brittle gray crystalline element that is a semiconducting metalloid (resembling silicon) used in transistors; occurs in germanite and argyroditechemical element, element - any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter argyrodite - a rare steel-gray mineral consisting of silver and germanium and sulfur germanite - a rare reddish-gray mineral consisting of a copper iron germanium sulfide semiconducting material, semiconductor - a substance as germanium or silicon whose electrical conductivity is intermediate between that of a metal and an insulator; its conductivity increases with temperature and in the presence of impurities |