THE MINERALS OF IDAHO 147 



CHALCOSTIBITE (117) 



Copper sulphantimonite, Cii2S.Sb 2 S 3 . Orthorhombic. 



Chalcostibite is a comparatively rare mineral which has been 

 doubtfully identified from one mine in Idaho. It is possibly present 

 elsewhere as a gray massive mineral lumped under the name "gray 

 copper,' 7 which rightly belongs to tetrahedrite, but which probably 

 includes a number of other minerals containing copper, sulphur, and 

 antimony, which can be identified only by a chemical analysis or by 

 crystal lographic study. 



SHOSHONE COUNTY 



A specimen of ''gray copper" collected by F. L. Ransome in the 

 Standard-Mammoth mine in the Coeur d'Alene district was tested 

 qualitatively by Dr. Waldemar T. Schaller, who concluded from its 

 closed tube reaction that it was probably chalcostibite rather than 

 the more common tetrahedrite. 23 The mineral is in grains a few milli- 

 meters in diameter intergrown with some chalcopyrite and sparsely 

 disseminated through milky white quartz containing occasional 

 patches of chloropal (?) and galena. Such material has been observed 

 frequently by the writer in the lower levels of both the Greenhill- 

 Cleveland and Standard-Mammoth ore shoots in narrow quartz 

 veins which are later than and cut the main mass of the ore. These 

 sometimes contained vugs in which were developed crystals of this 

 gray mineral up to 1 centimeter in diameter, of rhombic aspect, but 

 so shattered that they fell to pieces almost immediately. Chalco- 

 pyrite and chloropal ( ?) were usually associated with this mineral in 

 the quartz. 



GALENOBISMUTITE (118) 



Lead sulphobismuthite, PbS.Bi 2 S 3 . Orthorhombic. 



BOISE COUNTY 



The rare mineral galenobismutite, previously definitely known 

 only from the original locality in Nordmark, Sweden, has been 

 described from the Belzazzar mine in the Quartzburg district. 24 



The specimen, which was selected as a typical specimen of the ore, 

 came from the dump of the Belzazzar mine near the Jerusalem Valley 

 road, a little west of Quartzburg. It consists in the main of trans- 

 lucent to transparent crystalline white vein quartz. The sequence 

 of deposition of the minerals is not entirely clear, but there is a band 

 of more or less pure pyrite adjacent to the wall of the vein which 

 appears to be the earliest mineral of the ore. The quartz is slightly 

 sheeted parallel to the walls of the vein and small grains of pyrite 

 are distributed along the partings. Pyrite occurs also in crystalline 



23 F. L. Ransome. U. S. Oeol. Survey, Prof. Paper 62, p. 93, 1908. 



M Earl V. Shannon. On galenobismutite from a gold quartz vein in Boise County, Idaho. Jour. 

 Washington Academy of Science, vol. 11, pp. 298-300, 1921. 



