Briartite
Briartite is an opaque iron-grey metallic sulfide mineral, Cu2(Zn,Fe)GeS4 with traces of Ga and Sn, found as inclusions in other germanium-gallium-bearing sulfides.
It was discovered at the Prince Léopold Mine, Kipushi, Shaba, Congo (Léopoldville) in 1965 by Francotte and others, and named for Gaston Briart who had studied formations at Kipushi.