THE MINERALS OF IDAHO 



109 



sulphide in a 6 cm. rein of auriferous quartz-sulphide ore cutting 

 granite. 



BONNER COUNTY 



Sphalerite is found in moderate amount associated with galena in 

 lead-silver prospects and small mines in a number of places in Bonner 

 County. Only a small number of specimens have been available for 

 examination, and few of the ores have previously been described in 

 detail. No important production of zinc ore has been made and, 

 so far as known, the occurrences of sphal- 

 erite in this county show no features of 

 especial mineralogic interest. 



/ 



CUSTER COUNTY 



In the Bay Horse district sphalerite is 

 present in very subordinate amount in 

 the primary ore of the lead-silver deposits. 

 By its oxidation it has given rise to some 

 calamine and smithsonite. In the East 

 Fork (Copper Basin) district the existence 

 of sphalerite in the primary ore of the 

 Starr Hope mine is indicated by the 

 presence of smithsonite in the oxidized 

 ore. Near the head of the Middle Fork 

 of Lost River the ore of the Phi Kappa 

 prospect in Phi Kappa Canyon contains 

 granular sphalerite with galena and chal- 

 •copyrite in granular garnet rock. Some 

 sphalerite occurs also in a prospect near 

 the head of Little Fall Creek. 



In the Seafoam district a little sphal- 

 erite occurs with other sulphides as im- 

 pregnations in granite along fissures in 

 the Bulldog and other claims. In the 

 Sheep Mountain district sphalerite is found in considerable amount 

 in lead-silver ores of the Golconda, King, and other properties. 



In the Washington Basin district sphalerite occurs with pyrrhotite, 

 arsenopyrite, etc., in vein matter from the Empire group. A specimen 

 from the upper tunnel of the Empire shows considerable masses of 

 sphalerite in quartz. This material has a peculiar appearance and 

 has been mistaken for hubnerite. Specimens from a winze in the 

 lower tunnel of the Empire show coarse brilliant dark brown sphal- 

 erite in quartz with galena and arsenopyrite. Small vugs contain 

 brig] it crystals, one of which was measured and found to be bounded 

 by faces of the cube and plus tetrahedron. This crystal is figured 

 as Figure 6. 



Fig. 6.— Sphalerite crystal, showing 

 positive tetrahedron beveled by 

 narrow faces of the cube. empire 

 mine, Washington Basin district, 

 Custer County 



