petzite
/ˈpɛtsʌɪt/Mineralogy
noun
A rare mineral of the cubic crystal system consisting of a telluride of silver and gold with the approximate formula Ag3AuTe2, and occurring as metallic grey to black masses.
Origin
Mid 19th century; earliest use found in James Nicol (1810–1879), geologist. From German Petzit, from the name of W. Petz, the chemist who analysed the mineral + -it.