zinkenite

from WordNet (r) 3.0 (2006)

zinkenite
    n 1: a steel grey metallic mineral (a sulphide of lead and
         antimony)

from The Collaborative International Dictionary of English v.0.48

Zinkenite \Zink"en*ite\ (-en*[imac]t), n. [From Zinken, director
   at one time of the Hanoverian mines.] (Min.)
   A steel-gray metallic mineral, a sulphide of antimony and
   lead.
   [1913 Webster]