82 BULLETIN - 131, UNITED STATES NATIONAL MUSEUM 



CUSTER COUNTY 



Acicular steel gray needles of bismuthinite are present in massive 

 pyrite, and disseminated grains and fibrous masses in quartz and 

 altered granite, in the Empire Claims of the Idaho-Montgomery 

 Mining Co. in Washington Basin at the head of Salmon River in 

 Custer County. It is associated with a reddish sphalerite, pyrite, 

 and barite, and alters to earthy bismuth carbonates. 



WASHINGTON AND ADAMS COUNTIES 



Bismuthinite occurs sparingly in the contact metamorphic cop- 

 per deposits of the Seven Devils district and was doubtfully identified 

 as microscopic grains in disseminated low-grade ore of the Red 

 Ledge mine. 42 In the Heath district the same mineral is found in 

 grains and granular masses with argentiferous pyrite in copper ores 

 associated with garnet rock. 43 



GUANJUATITE (30) 

 Bismuth selenide, Bi 2 Se 3 . Orthorhombic • 



LEMHI COUNTY 



Guanajuatite is a very rare mineral which was known only as 

 specimens from Guanajuato in Mexico until identified in specimens 

 from Idaho by Dr. W. T. Schaller. 44 It occurs as dark gray grains 

 and small masses (Cat. No. 93736 U.S.N.M.) in quartz in a claim 

 belonging to Mr. John E. Ericksen, of Salmon, Idaho. The claim is 

 located on Kirtley Creek. 9 miles northeast of Salmon and 1^ miles 

 from the mouth of the creek. 45 



TETRADYMITE (31) 

 Bismuth telluride, Bi 2 TeS 2 . Rhombohedral. 



CUSTER COUNTY 



Tetradymite has been reported to occur in the ores of the Empire 

 claims of the Idaho-Montgomery Mining Co. in Washington Basin. 46 

 The report has not been confirmed. All specimens showing bismuth 

 minerals from this locality which were tested for tellurium by the 

 writer gave negative results. 



MOLYBDENITE (34) 



Molybdenum sulphide, MoS 2 . Hexagonal. 



BONNER AND BOUNDARY COUNTIES 



Molybdenite occurs on A. J. Kent's property near the road that 

 runs to the Dora and Tungsten Hill tungsten mines. The country 

 rock is granite and the mineral is found in a pegmatitic phase of 



42 D. C Livingston and F. B. Laney. The copper deposits of the Seven Devils and adjacant districts. 

 Idaho State Bur. Mines and Oeol., Bull. 1, pages 52 and 66, 1920. 

 " R. N. Bell. Annual Report on Mining Industry of Idaho for 1905, page 141. 

 « Waldernar T. Schaller. U. S. Oeol. Survey, Bull. 610, p. 137, 1916. 

 « John E. Ericksen. Personal letter, 1916. 

 < 6 Engineering and Mining Journal, vol. 83, p. 23, 1907. 



