THE MINERALS OF IDAHO 437 



In the Last Chance mine at Wardner much of the cerusite of the 

 richest oxidized ore was dusted with bindheimite and in the adjoining 

 Tyler mine this mineral was of frequent occurrence. 



The Caledonia mine, west of Wardner, produced much ore in 

 which the valuable metals were entirely in the form of bindheimite, 

 masses of nearly pure friable bindheimite several feet in diameter 

 being exposed at times in the oxidized ores and having the same 

 attitude as masses of tetrahedrite in the unoxidized portions of the 

 vein. Sulphantimonites other than tetrahedrite have not been noted 

 in this mine and the bindheimite seems to represent a pseudomorph, 

 in most cases, after tetrahedrite and to have formed by reaction 

 between the lead in solution and the antimonial mineral in place. 

 A reversal of this relation is shown by the occurrence of lumps of 

 galena surrounded by crusts of bindheimite. Furthermore a single 

 specimen of soft yellow bindheimite was obtained from the Caledonia 

 mine which had the typical granular structure and traces of the 

 cubic cleavage of galena. 



A specimen of ore from the Northern Light mine on Pine Creek 

 consists of quartz containing galena largely oxidized to greasy masses 

 of cerusite. Vuggy portions contain a canary-yellow lusterless 

 material which is friable and has an acicular structure pseudo- 

 morphous after some fibrous sulphide. This yellow material, which 

 is doubtless bindheimite, is reduced on charcoal before the blowpipe 

 to a black globule, whch reacts for lead and antimony. Under the 

 microscope the mineral is transparent and isotropic with an index of 

 refraction much higher than 1.84. 



This mineral has been noted in specimens from the Lookout 

 Mountain and Carbonate mines, on Pine Creek, and also in ore from 

 the Hypotheek mine south of Kingston. A specimen of lusterless 

 compact yellow bindheimite from the Hypotheek mine was analyzed 

 with the following results : 



Analyses of bindheimite from the Hypotheek mine 



(E. V. Shannon, analyst) 



Per cent 



Insoluble (quartz) 2. 28 



Lead oxide (PbO) 53. 48 



Antimony pentoxide (Sb 2 5 ) 36. 54 



Ferric iron oxide (Fe 2 3 ) 3. 84 



Carbon dioxide (C0 2 ) . 60 



Water above 110° C 3. 27 



Water below 110° C . 30 



Total 100.31 



