orpiment, getchellite and stibnite from zarshuran deposit, nw iran, exhibit extensive as-sb substitution. there are four known minerals along as2s3-sb2s3 join, i.e. orpiment (as2s3), wakabayashilite [(as,sb)20s30], getchellite (assbs3) and stibnite (sb2s3). extensive mineralogical studies by scanning electron microscope (sem) and electron probe micro-analyzer (epma) indicate that getchellite fr...
