Source : Webster's Revised Unabridged Dictionary (1913)

Lepidomelane \Lep`i*dom"e*lane\
   (l[e^]p`[i^]*d[o^]m"[-e]*l[=a]n), n. [Gr. lepi`s -i`dos, a
   scale + me`las, me`laina, black.] (Min.)
   An iron-potash mica, of a raven-black color, usually found in
   granitic rocks in small six-sided tables, or as an
   aggregation of minute opaque scales. See {Mica}.

Source : WordNet®

lepidomelane
     n : a mica that is a biotite containing iron