202 BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



CLEARWATER COUNTY 



A sample of coarse concentrates separation product (Cat. No. 

 87,506, U.S.N.M.) from gravels at Pierce consists very largely of 

 rutile in red-black waterworn pebbles and fragments of crystals up 

 to % inch in diameter. These are mostly red-black in color but 

 some are brown, yellow, or greenish in small fragments under the 

 microscope. Associated with the rutile are tourmaline, corundum, 

 epidote, ilmenite, and some rarer minerals. 



SHOSHONE COUNTY 



A single small specimen found as float by Mr. Oscar H. Hershey in 

 1920 on the Lookout Mountain claim, east of the forks of Pine Creek, 

 contains small reddish to steel gray needles of rutile in a narrow quartz 

 seam cutting rusty spotted quartzite from the middle member of the 

 Prichard formation. 



PLATTNERITE (251) 

 Lead dioxide, Pb0 2 . Tetragonal. 



Previous to its discovery in the Coeur d'Alene district, plattnerite 

 was known as two or three specimens from European localities, and 

 its composition, crystallization, and, in fact, its validity as a species 

 were imperfectly established. 



LEMHI COUNTY 



In the Democrat mine of Frank Grooms in the Gilmore district, 

 plattnerite in massive form was found embedded in specimens of 

 fine red minimum. 12 



SHOSHONE COUNTY 



In 1888, Waldo Clark, of Mullan, Idaho, transmitted to the Smith- 

 sonian Institution some specimens which were found upon examina- 

 tion to be plattnerite. A considerable amount of this material was 

 secured, and subsequent study placed the mineral as a distinct species 

 of tetragonal crystallization. 13 



The plattnerite came from the You Like lode, now a part of the 

 Morning mine at Mullan, in the Coeur d'Alene district. It was found 

 in the vein in the uppermost tunnel, 70 feet below the surface, as 

 rounded nodules touching each other in a continuous line for a dis- 

 tance of 20 feet, when it gave out for 10 feet in a space occupied by 

 limonite, beyond which there was considerable more plattnerite 

 for 10 to 15 feet, when it disappeared and no more was found in the 

 40 feet the tunnel continued. It was associated with limonite in 

 botryoidal masses (pi. 13) and as brown ocher. The only other 

 associated mineral was a white pyromorphite in crystals, rarely in 

 veins, scattered through the botryoidal nodules of plattnerite, 



1J E. V. Shannon. Amer. Mineralogist, vol. 2, pp. 15-17, 1912. 



» W. S. Yeates and W. Ayres. Amer. Journ. Sci., vol. 43, p. 407, 1892. 



