The Collaborative International Dictionary of English v.0.48:

Zarnich \Zar"nich\, n. [F., fr. Ar. az-zern[imac]kh, fr. Gr. ?.
   See Arsenic.] (Min.)
   Native sulphide of arsenic, including sandarach, or realgar,
   and orpiment.
   [1913 Webster]