THE MINERALS OF IDAHO 



141 



ELMORE COUNTY 



Arsenopyrite occurs with gold in the Neal and Rocky Bar districts. 

 Specimens from the Vishnu mine, Rocky Bar district show it as 

 reddish-tarnishing gray masses and imperfect crystals in quartz. 



IDAHO COUNTY 



Arsenopyrite is reported from the Goodenough and other gold 

 veins in the Warren district. A specimen of ore from the South 

 Fork mine, 7 miles southwest of Elk City, Elk City district, shows 

 small sharp steel-gray crystals of this mineral in quartz. 



LEMHI COUNTY 



Arsenopyrite occurs in gold ores of the Mineral Hill district. The 

 cobaltiferous variety, danaite, which is common in the cobalt ores 

 of the Blackbird district is described below (page 143). 



OWYHEE COUNTY 



In Owyhee County arsenopyrite is associated with sphalerite, 

 galena, etc., in the lead ores of the South Mountain district. A speci- 

 men from the Bay State mine dump, this district, has abundant 

 arsenopyrite with some black sphalerite and a little galena and 

 chalcopyrite. The arsenopyrite is well crystallized in crystals of 

 simple habit up to 1 cm. long. 



SHOSHONE COUNTY 



Arsenopyrite is a rather uncommon mineral in the Coeur d'Alene 

 district and is practically absent from the larger lead-silver mines. 

 Small crystals have been noted in slaty sericitic rock adjacent to 



Figs. 20-21.— Arsenopyrite. Small crystals embedded in slate. 



Burke, Shoshone County 



Stanley Antimony mine, 



small quartz veins containing jamesonite in the stope above the 2,000 

 foot level of the Standard Mammoth mine at Mace. Iron gray 

 crystals of the forms shown in Figures 20 and 21 occur in slaty rock 

 inclusions in the quartz-stibnite ore of the Stanley antimony mine in 

 Gorge Gulch above Burke. This arsenopyrite has a dull lead gray 



