COLORADO FERBERITE AND THE WOLFRAMITE SERIES. 



By FRANK L. HESS and WALDEMAR T. SCHALLER. 



THE MINERAL RELATIONS OF FERBERITE. 



By FRANK L. HESS. 



GEOGRAPHY AND PRODUCTION. 



, as ordinarily defined, is that mineral qf_,the 

 series which is composed wholly or almost wholly of iron tungsuue. 

 and which, like other wolframites, crystallizes in the monoclinic sys- 

 tem. It is comparatively rare and in most places where found it seems 

 to occur in small quantities only. It occurs in largest quantity in 

 Colorado, about 25 miles northwest of Denver, 

 County, though the dep'ositsextend a short 

 beyond the county line into the north end of Gilpin County. From 

 this area, which has a southwest-northeast length of about 12 miles 

 and a width of 6 to 7 miles, an equivalent of probably 7,300 short 

 tons of concentrates carrying 60 per cent WO 3 had been mined from 

 1901, when exploitation of the tungsten veins began, to the close 

 of 1912. 



The relative importance of the Boulder tungsten field, as the area 

 is generally known, is indicated by the statistics of the production 

 of tungsten ore in 1910, in which year the output of the field was 

 1,221 tons. In the same year the output of Queensland was 1,145 

 tons; Portugal, 1,132 tons; Argentina, 1,061 tons; and the world's 

 production was probably about 7,500 tons, the remainder being 

 smaller lots from many countries. 1 The tungsten-bearing mineral 

 produced from the three countries named was wolframite, and no 

 other count ry produced any considerable quantity of ferberite. 



Foi details see Hess, F. L., Tungsten: U. S. Oeol. Survey Mineral Resources, 1910, pt. 1, p. 734, 1911. 

 Since the above paragraph was written the world's statistics for 1911 and 1912 have become available, and 

 these show that Burma has outstripped all other producers, its output of wolframite being equivalent to 

 2,095 short tons of ore carrying 60 percent WO. (See U. S. Geol. Survey Mineral Resources, 1911 and 1912.) 



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