THE MINERALS OF IDAHO 75 



copious precipitate of silver chloride with hydrochloric acid. The 

 amalgam apparently contains more gold than silver. It seems 

 probable, from a study of this sample, that the gold and mercury 

 have been derived from different sources and that amalgamation has 

 taken place in the gravels. That the mercury is native and not lost 

 from placer mining operations is indicated by the abundance of 

 cinnabar. 



LEAD (18) 

 Lead, Pb. Isometric. 



Native lead is a very rare mineral which has been found in two 

 widely separated districts in Idaho. 



BLAINE COUNTY 



In Blaine County, in the Wood River district, native lead has been 

 found with minium at the Jay Gould mine in the midst of masses of 

 galena. The metallic lead is in the form of small rounded grains 

 from 3 to 5 mm. in diameter and sometimes in irregularly reniform 

 bunches weighing 25 grams or more, usually coated with minium. 27 

 Other specimens show native lead without any galena, running 

 through a mass of quartz which is stained red by minium. The 

 quartz is somewhat cracked and the pieces are held in place by fila- 

 ments of lead. A white coating of lead carbonate appears in a few 

 small cavities. The lead is argentiferous. 28 



A specimen from near Hailey (Cat. No. 48832, U.S.N. M.) received 

 from Baldwin Moore in 1890 consists of native lead in masses and 

 filaments with galena in compact anglesite of a gray color. 



In 1923 C.P.Ross, of the United States Geological Survey, obtained 

 a small specimen of native lead from the Arizona mine a little north of 

 the Bullion. 



SHOSHONE COUNTY 



In the Coeur d'Alene district, in Shoshone County, a single speci- 

 men from the upper workings of the Mammoth mine at Mace showed 

 native lead as two stout wires projecting from a mass of granular 

 galena. 29 The material occurring in many mines and especially in 

 certain stopes of the Bunker Hill mine, which is called "pure lead" 

 by the miners, is a very finely compacted form of galena which is 

 sectile, soft, and shows no granular structure. 



PLATINUM (20) 



Platinum alloyed with iron and other metals. Pt., Fe. Isometric. 



Platinum in very small amount has been reported to occur in a 

 number of counties in Idaho, but definite data amplifying these several 



» W. P. Blake. Amer. Jour. Sci., ser. 3, vol. 25, p. 161, 1883. 

 « W. F. Ilillebrand. U. S. Geol. Survey, Bull. 20, p. 99, 1885. 

 M W. Howard McBride. Oral communication, 1911. 



