96 



UNIVERSITY OF COLORADO STUDIES 



No. 4. Wolframite. Johnny Ward's Mine, Ward, Colorado. 



Per cent. 

 W0 3 



Si0 2 



FeO 



MnO 



CaO 



FeS 2 



No. 5. Hubnerite. Natalie Mine, Silverton. Colorado. 



Per cent. 

 W0 3 



Si0 2 



FeO 



CaO 



MnO 



A1 2 3 



No. 6. Hubnerite-Wolframite. Sultan, Mt. Silverton, Colorado. 



Per cent. 



W0 3 7409 



Si0 2 • 43 



FeO 1107 



MnO 14.35 



99.94 



No. 7. Wolframite. Near Lead, Black Hills, South Dakota. 



Per cent. 

 W0 3 48.26 



Si0 2 26 . 21 



C0 2 2.67 



FeO 10 . 00 



CaO 3 . 40 



MnO 7.56 



A1 2 3 1.56 



99.66 



Chemical Laboratory, University of Colorado, Oct. 26, 1908. 



