franckeite
/ˈfraŋkəaɪt/Mineralogy
noun
A lead sulphide mineral also containing tin, iron, and antimony, typically found in association with metamorphic tin deposits and occurring as lustrous greyish-black tabular crystals, notably in the tin mines of Bolivia.
- Formula FePb5Sn3Sb2S14. Crystal system: triclinic..
Origin
Late 19th century; earliest use found in Journal of the Chemical Society. From German Franckeit from the name of Carl Francke and Ernst (also Ernest) Francke, German mining engineers, who discovered the mineral + -it, with remodelling of the ending after -ite.