594 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



BOOLANGEEITE FROM SUPEKIOtt, MONTANA. 



Boulangerite was a constant constituent of the zinc ore in a vein 

 mined at the Iron Mountain Mine, Superior, Montana, occurring in 

 all of the ore as small disseminated grains and fibers in fine granular 

 sphalerite, and as bunches of coarse fibers with coarse granular dark- 

 brown sphalerite in white quartz, A specimen of typical material 

 in the United States National Museum shows course-fibrous steel-gray 

 boulangerite, with sphalerite in pure white vitreous vein quartz. 

 Upon analysis the material of this occurrence, having a brownish 

 streak and a specific gravity of 6.274, gave the following results : 



Analyses of J^oulntujcritc from Superior, Montana. 



BOULANGKRITE FROM THE NORTH STAR MINE, IDAHO. 



The United States National Museum has recently acquired several 

 specimens of the typical mixed ore of the North Star Mine, Wood 

 River district, Blaine County, Idaho. This mine at one time made a 

 considerable production of lead-silver ore from workings within the 

 oxidized zone. When the primary mineralization of the vein was 

 encountered it was found to consist of such refractory mixtures of 

 diverse minerals that the ore could not be mined at a profit, and 

 the mine remained closed for a number of 3^ears. Within the past 

 few years new operators have opened the property and have been 

 attempting, by modern metallurgical methods, to separate the valu- 

 able minerals of the ore, but with indijfferent success. 



The ores are reported to consist of intimate mixtures of galena, 

 sphalerite, chalcopyrite, pyrite, pyrrhotite, arsenical pyrite, and 

 '' antimony " in a gangue of quartz. The specimens in the United 

 States National Museum collections show galena, pyrite, dark brown 

 sphalerite, arsenopyrite, and a gray antimonial mineral in a gangue 

 of quartz, or, in one case, crystalline dolomite. The gray mineral 

 which heretofore has evidently been mistaken for stibnite is, so far 

 as tested, all boulangerite. This boulangerite is a constant constituent 

 of the ore, not only of the Star mine, but also of a number of ad- 

 joining mines, and the total amount of ore in which it forms a 

 prominent constituent must amount to many thousands of tons. 

 The arsenopyrite which is abundant in the ore has a peculiarly brassy 

 yellow color, like pyrite, which disappears when it is immersed in 



