ABT. 24 BENJAMINITE^ A NEW MINEEAL — SHANNON 



Analysis 2 of beajaminite {recalculated). 



The deducted impurities are quartz 12.83 per cent, molybdenite 

 0.77 per cent and chalcopyrite 5.36 per cent. 



Analysis 3 is the most dependable analysis of the four since the 

 material was not only well selected but the method most suited for 

 the several separations had been determined by the previous work. 

 The powder used for analysis was, moreover, treated to a magnetic 

 separation whereby a large part and possibly all of the chalcopyrite 

 was removed. Although the iron found is considered below to be 

 present as admixed chalcopyrite which is deducted, it is possible 

 that the amount found in this analysis is essential to the benjaminite 

 occurring as an isomorphous replacement of the lead. This would 

 not affect the formula below derived but would rather tend to support 

 it by bringing the analytical results into closer agreement with the 

 calculated percentages. The analysis is as follows: 



Analysis 3 of benjaminite. 



45554— 25— Proc.N.M.vol.65- 



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