THE MINERALS OF IDAHO 211 



LEMHI COUNTY 



In the Parker Mountain mine, Parker Mountain district, earthy 

 l>lack manganese oxide, probably psilomelane, occurs as a friable 

 powder and also impregnating aragonite giving black rosettes. 

 Specimens from the incline shaft, No. 4 tunnel of the Patterson 

 Creek tungsten mine, Blue Wing district, show dull black plumose- 

 fibrous psilomelane resting on drusy quartz. 



SHOSHONE COUNTY 



Psilomelane is probably widespread in occurrence in the oxidized 

 lead-silver ores of the Coeur d'Alene district in impure earthy form 

 or mixed in small proportion with limonite. The characteristic 

 gangue mineral in the unoxidized ores of this district is manganifer- 

 ous siderite, and this, upon oxidation, yields mixed iron and manga- 

 nese oxides. Much of the limonite is darker brown in color than is 

 common for this mineral, due to the manganese content. 



Earthy ocherous manganese oxide was found as a soft streak 

 containing heavy masses of pearly white cerusite in the McBride 

 lease on the Tyler mine in 1912. The best psilomelane thus far found 

 in Idaho came from the 500-foot level of the Caledonia mine where 

 it occurred on the level near the old inclined shaft as a streak ol 

 black ocherous material up to 2 feet wide containing coherent botry- 

 oidal steel gray to iron-black masses made up of separable concentric 

 shells. Steel-gray impregnations of psilomelane are common in 

 quartzite on the surface at many places in the district, having been 

 particularly noted in the vicinity of the outcrop of the Caledonia 

 vein and at the east foot of Haystack Peak. 



During the war demand for manganese a number of prospects 

 were explored in search of manganese ore of commercial grade. 

 Ore from none of these has been examined by the writer, and in the 

 absence of definite mineralogical data they are referred to here, 

 since the manganese mineral is most probably psilomelane. The 

 principal prospects have been mentioned by Livingston. 190 The 

 Cummings property, 1 mile east of Prichard, has opened a low-grade 

 deposit showing manganese oxide cementing a brecciated quartzite 

 of the Revett formation and the Butte-Detroit claim, 2 miles below 

 Delta, has exposed a similar manganiferous zone 65 feet wide in the 

 same formation. The lone group, on the top of the ridge between 

 Bear and Paragon Gulches, has found low-grade manganiferous 

 material in the oxidized portion of a lead-bearing vein. The Waring 

 property on Ninemile Creek, 3 miles from Wallace, and the Vienna- 

 International mine, 7 miles from Wallace, on Placer Creek, have 

 prospected for manganese ore in brecciated zones carrying manganese 

 oxide as a cement. 



1!a D. C. Livingston. Univ. of Idaho School of Mines, Bull. 2, pp. 37-39, 1919. 



