polyargyrite
/ˌpɒlɪˈɑːdʒɪrʌɪt/Mineralogy. Now rare
noun
A mineral consisting of a sulphide and antimonide of silver, subsequently shown to be a mixture of argentite and tetrahedrite.
Origin
Late 19th century; earliest use found in James Dana (1813–1895), geologist, zoologist, and teacher. From poly- + argyrite, after German Polyargyrit.