COMPOSITION OP FAHLERZ AND EMBOLITE. 153 



2._N0TES ON THE COMPOSITION OF FAHLERZ 



AND EMBOLITE, FROM NEW SOUTH WALES. 



By G. S. Mackenzie, Ph.D., F.I.C. 



I. — Fahlerz. 

 A crystalized specimen of this mineral, from the Webb Mine, 

 near Emmaville, district of New England, was submitted to 

 analysis with the following i*esult : — 



Or a composition most nearly corresponding to (R" S4) Sb^ S3 = 



R" Sbg Sy, where R" = (Cu. Ag. Fe. Zn). 



Finding R" for the various metals, silver being taken as 0.5, 



we have — 



/140 10 27 13 x 



( Cu. — Ag. Fe. Zn ) 7 S4, + Sba S3 



\190 190 190 190 y " ^ 



This corresponds closely to an analysis of Fahlerz, from 

 Germany, by Kiihlemann (vide Dana, " Mineralogy," p. 102. 

 Analysis No. 22). 



It therefore contains considerably less sulphur than that 

 demanded by the general formula given in Dana's " Mineralogy" 

 RS4 Sh., S;. This may, possibly, be accounted for by impurity 

 or mechanical mixture of another mineral. The specimen analysed 

 was a carefully selected, fully crystallised, twin tethrahedron 

 crystal. 



The mineral occurs closely associated with galena, arsenical 

 pyrites, and a Little zinc-blende, in a felstone and quartz matrix. 



