pyrrhotite

from WordNet (r) 3.0 (2006)

pyrrhotite
    n 1: a brownish iron sulfide mineral (FeS) having weak magnetic
         properties [syn: {pyrrhotite}, {pyrrhotine}, {magnetic
         pyrites}]

from The Collaborative International Dictionary of English v.0.48

Pyrrhotine \Pyr"rho*tine\, Pyrrhotite \Pyr"rho*tite\, n. [Gr. ?
   flame-colored, fr. ? fire.] (Min.)
   A bronze-colored mineral, of metallic luster. It is a
   sulphide of iron, and is remarkable for being attracted by
   the magnet. Called also {magnetic pyrites}.
   [1913 Webster] pyrrol