THE MINERALS OF IDAHO 213 



Blackbird district in Lemhi County. 21 A lot of this material from 

 the Togo claim in that district consists in the main of a friable dull 

 black powder, although one fragment of schist shows blue-black 

 crusts along cracks made up of minute globules with dull metallic 

 luster. This black earthy material dissolves readily in hydrochloric 

 acid with evolution of chlorine and in concentrated acid yields a 

 deep blue-green solution which flashes to brownish pink upon dilu- 

 tion. An analysis of this asbolite gave the following results : 



Analysis of asbolite from Lemhi County 



(E. V. Shannon, analyst) 



Per cent 



Insoluble and silica 2. 20 



Ferric oxide and alumina (Fe 2 03, AI2O3) 2. 50 



Manganese dioxide (Mn0 2 ) 49. 64 



Cobalt dioxide (Co0 2 ) 5. 12 



Cobaltous oxide (CoO) 13. 08 



Lime (CaO) 6. 10 



Magnesia (MgO) 1. 00 



Cupric oxide (CuO) 1. 56 



Water below 110° C 10. 88 



Water above 110° C 8. 24 



Total 100. 32 



In the above statement the oxygen is calculated first with the MnO 

 until that is used up and the balance is united with the cobalt and 

 stated as Co0 2 . Otherwise stated, the results of the analysis are as 

 follows: 



Per cent 



Insoluble 2. 20 



Manganous oxide (MnO) 40. 50 



Copper oxide (CuO) 1. 56 



Cobalt oxide (CoO) 17. 30 



Lime (CaO) 6. 10 



Magnesia (MgO) 1. 00 



Oxygen (O) excess 10. 04 



Water above 110° 8. 24 



Water below 110° 10. 88 



Ferric oxide and alumina 2. 50 



Total 100. 32 



The material is thus a typical asbolite. 



DELAFOSSITE (269a) 



Copper iron oxide (Cuprous metaferrite), Cu 2 O.Fe 2 3 . Rhombohedral. 



LEMHI COUNTY 



A black mineral occurring as streaks in a whitish sandy rock 

 forming copper ore of the Pope Shenon mine in Lemhi County 

 collected by C. P. Ross of the United States Geological Survey has 



» J. B. Umpleby. U. S. Geol. Survey, Bull. 528, p. 75. 1913. 



