onofrite
/ˈɒnə(ʊ)frʌɪt/Mineralogy
noun
A sulphide and selenide of mercury occurring as lustrous black masses.
Origin
Mid 19th century; earliest use found in James Nicol (1810–1879), geologist. From German Onofrit from the name of San Onofre in Mexico, where it was first identified + -it.