nBournonite(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.
Century Dictionary and Cyclopedia
nbournoniteA sulphid of antimony, lead, and copper, of a steel-gray color and brilliant metallic luster, found in the Harz mountains, Cornwall, and Mexico. Wheel-ore is a variety which owes its name to the form of the twin crystals, resembling a cog-wheel. Also called endellionite.