The Collaborative International Dictionary of English v.0.48:

Bournonite \Bour"non*ite\, n. [Named after Count Bournon, a
   mineralogist.] (Min.)
   A mineral of a steel-gray to black color and metallic luster,
   occurring crystallized, often in twin crystals shaped like
   cogwheels (wheel ore), also massive. It is a sulphide of
   antimony, lead, and copper.
   [1913 Webster]