plagionite
/ˈpleɪdʒɪənʌɪt/Mineralogy
noun
A rare blackish grey mineral occurring as thick, tabular crystals of metallic appearance and consisting of a monoclinic sulphide of lead and antimony, Pb5Sb8S17.
Origin
Mid 19th century; earliest use found in Thomson's Records General Science. From German Plagionit from ancient Greek πλάγιος oblique + -n-, connective element (perhaps representing the final letter of the neuter form πλάγιον) + German -it.