The Collaborative International Dictionary of English v.0.48:

Neogen \Ne"o*gen\ (n[=e]"[-o]*j[e^]n), n. [Neo- + -gen.] (Chem.)
   An alloy resembling silver, and consisting chiefly of copper,
   zinc, and nickel, with small proportions of tin, aluminium,
   and bismuth. --Ure.
   [1913 Webster]