NO. 2351. NOTES ON METALLIC MINERALS— SHANNON. 595 



dilute hydrochloric acid. It forms slender prismatic crystals, averag- 

 ing 1 centimeter long by 1 millimeter in diameter, showing usually 

 only the unit prism, terminations being very rare. 



The boulangerite has the usual steel-gray color and metallic 

 luster and exhibits the characteristic brownish streak. It occurs 

 as compact parallel-fibrous masses, as slender needles lining cavities, 

 and as compact and slightly schistose massive forms with other 

 sulphides, the massive variety evidently having been subjected to 

 pressure. The boulangerite is commonly the youngest mineral of the 

 vein, and it often lines cavities or occupies the spaces between the 

 crystals making up quartz combs. Upon analysis a sample of the 

 boulangerite gave the results in column 1 below. In column 2 the 

 analysis is recalculated to 100 per cent after deducting gangue. 



Analysis of houlangerite from the North Star mine, Idaho. 



^"*>"-'-hfa!'^'"'- 



Lead 



Silver 



Iron 



Antimony.. 



Arsenic 



Sulphur 



Insoluble... 



Total . 



99. 89 ! 100. 00 



BOULANGERITE FROM THE INDEPENDENCE MINE, IDAHO. 



A specimen from the Independence Mine, Wood River mining 

 district, Idaho, consists of coarse granular white vein quartz con- 

 taining abundant small pyritohedral crystals of pyrite and fibrous 

 masses of boulangerite. One side of the specimen bears a felted or 

 curved fibrous mass of steel gray boulangerite, and a joint surface 

 which bounds the specimen on one side bears small rosettes of radi- 

 ating, deeply striated, short prismatic crystals of boulangerite 

 showing well-defined cleavage parallel to the elongation. In color 

 the boulangerite is rather light silver-gray and its streak is brown- 

 ish-gray on paper and distinctly brown on porcelain. A selected 

 sample of the compact, curved, fibrous material gave upon analysis 

 the results tabulated below : 



Analysis of boulangerite, Independence Mine, Idaho. 



Insoluble 3. 58 



Lead 53. 79 



Silver Trace. 



Iron , 41 



Antimony 23. 83 



Arsenic . 12 



Sulphur 18. 11 



Total 99. 84 



