or·pi·ment /ˈɔrpəmənt/
  雌黃
  Or·pi·ment n.  Chem. Arsenic sesquisulphide, produced artificially as an amorphous lemon-yellow powder, and occurring naturally as a yellow crystalline mineral; -- formerly called auripigment.  It is used in king's yellow, in white Indian fire, and in certain technical processes, as indigo printing.
     Our orpiment and sublimed mercurie.   --Chaucer.
  Red orpiment, realgar; the red sulphide of arsenic.
  Yellow orpiment, king's yellow.
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  orpiment
       n : a yellow mineral occuring in conjunction with realgar; an
           ore of arsenic