KNOPF: PLUMBOJAROSITE FROM NEVADA 



499 



ferric iron, the higli content of bismuth, and the noteworthy 

 amount of copper, an element not present in considerable quanti- 

 ties in the previously pubUshed analyses of plumbojarosite. 



Analyses of plumbojarosite 



The presence of this copper suggested the possibility that 

 the analyzed material contains an admixture of beaverite 

 (CuOPbOFe2032S034HoO), a mineral recently discovered by 

 Butler, and shown by him to occur in some abundance in the oxi- 

 dized ores of Utah. 5 Under the microscope the optical prop- 



* Butler, B. S., and Schaller, W. T., Some minerals from Beaver County, 

 Utah. Am.Jour.Sci.,4thser.,32: 418. 1911. Butler, B.S., Occurrence of complex 

 and little known sulphates and sulpharsenates as ore minerals in Utah. Econ. 

 Geology, 8: 316-318. 1913. 



