126 



BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



BLAINE COUNTY 



Pyrite occurring in the gold veins of this county is auriferous, as 

 in the Camas, Tip Top, Croesus, Wide West, and other mines. A 

 specimen from the Croesus mine in the Hailey gold belt shows rather 

 highly modified pyrite crystals in quartz. One crystal from this 

 specimen was measured and had the forms and habit shown in 

 Figure 7. The forms and angles measured are given in the following 



table : 



Measurements of pyrite from Croesus mine 



The crystals, though small, rarely reaching 5 mm. in diameter, 

 are lustrous and yield excellent reflections. They are easily sepa- 

 rated from the inclosing quartz gangue. The specimen from which 

 the measured crystal was taken is labeled as from the stope on the 

 long 5 drift on the fourth level, Croesus mine. 



A specimen of ore from the Parker mine, Warm Springs district, 

 shows brilliant and modified pyrite crystals in coarse white calcite 

 associated with quartz containing sphalerite. One of these which 

 was measured had the forms and habit shown in Figure 8 and gave 

 the following measurements: 



Measurements of pyrite from Parker mine 



Specimens from the fifth level of the Muldoon mine, Little Wood 

 River (Muldoon) district, contain numerous well-formed pyrite 

 crystals of pyritohedral habit embedded in sericite. 



