THE MINERALS OF IDAHO 93 



tunnel of the Golden Age mine shows galena as relatively coarse 

 grains with sphalerite, pyrite, and tetrahedrite admixed with crushed 

 quartz in altered sericitized granite. Ore from the Gem of the 

 Mountains mine lias coarse granular galena with pyrite and arsenopy- 

 rite in quartz and in ore from the Overlook mine galena in perfect 

 cubic cleavages up to 1 centimeter in diameter occurs with pyrite, 

 sphalerite, and tetrahedrite. In some specimens from the latter 

 mine the gangue contains calcite and in one instance the galena 

 crystals are surrounded by a thin layer of chalcopyrite which pene- 

 trates them along cleavage cracks and is evidently of later age. 



In the TVestview (Willow Creek, Pearl, Kock Creek) district 

 galena is a common constituent of the masses of auriferous sulphides 

 which make up the primary gold ores in granite. In ore from the 

 Checkmate mine this mineral is intergrown with pyrite and sphalerite 

 in 3 cm. seams of metallic sulphides in quartz-seamed altered granite 

 containing disseminated arsenopyrite. Ore from the Lincoln mine 

 has small crystals of galena of cuboctahedral habit in vugs in masses 

 of brown sphalerite. The galena from this district is frequently 

 highly auriferous; a pure specimen from the Sacramento mine assayed 

 S ounces of gold and 07 ounces of silver a ton. 



BONNEK COUNTY (including BOUNDARY COUNTY) 



Galena occurs in a number of lead prospects and partly developed 

 mines in Bonner and Boundary counties. 



In the East Shore or Clark Fork district the principal lead mine is 

 the Lawrence, 13^ miles northeast of Clark Fork. The ore here is 

 clean galena in veins and lenses up to 3 feet wide. It is very pure, 

 showing only a little sphalerite and pyrite and some siderite gangue. 

 Much of it exhibits gneissic structure and highly polished galena 

 veneered slickensides are found in the ore. In the Marguerite pros- 

 pect on Trestle Creek about 1 mile north of the lake, galena occurs 

 in quartz with pyrrhotite, sphalerite, and chalcopyrite. This mineral 

 also occurs in the Morning Star vein 1 mile east of Hope with chal- 

 copyrite and sphalerite in a quartz gangue. The production of the 

 district has been small. 



In the Mooyie Yaak district galena occurs with native gold in the 

 Buckhorn and Dora mines and associated with chalcopyrite and 

 sphalerite in the Copper Queen mine and other prospects. 



In the Pend d'Oreille district some galena-bearing silver ores have 

 have been developed especially about Blaektail Mountain where the 

 galena is associated with tetrahedrite. 



CUSTEB COUNTY 



In the Alder Creek district only small amounts of galena have 

 been found. On the Kennedy group claims near mineral monument 



