Source : Webster's Revised Unabridged Dictionary (1913)

Staurolite \Stau"ro*lite\, n. [Gr. ? a cross + -lite.] (Min.)
   A mineral of a brown to black color occurring in prismatic
   crystals, often twinned so as to form groups resembling a
   cross. It is a silicate of aluminia and iron, and is
   generally found imbedded in mica schist. Called also
   {granatite}, and {grenatite}.