novákite
/ˈnəʊvɑːkʌɪt/ /ˈnəʊvakʌɪt/(also novakite) Mineralogy
noun
A monoclinic arsenide of copper and silver, Cu20AgAs10, occurring in the Krkonose mountains of the northern Czech Republic, which is steel-grey on fresh fracture but becomes almost black on exposure to air.
Origin
1950s; earliest use found in American Mineralogist. From German Novákit from the name of Jiří Novák, Czech mineralogist + -it.