THE MINERALS OF IDAHO 171 



containing 75 per cent of silver from the Morning Star discovery- 

 shaft was on exhibition in a Portland bank with a shipment of silver 

 bullion/ 7 This mineral is also common in the ores of the Flint 

 district in massive form in quartz. Except for their cleavage these 

 masses resemble tetrahedrite. This mineral has been noted in the 

 ore from the the Rising Star mine, and is reported to have occurred 

 with stephanite and xanthoconite in the rich ores first mined in the 

 district. 58 A specimen from a vein in drift 500 feet north, 2,650 

 feet from the portal of the Rich Gulch mine, west slope of Florida 

 Mountain, Silver City district, shows a narrow quartz vein averaging 

 1 cm. in width inclosed in greatly sericitized rock. The quartz is 

 drusy along the center and the druses are lined with polybasite in 

 minute but sharp and brilliant hexagonal thin tabular crystals. 

 One of these was measured and found to have the forms and develop- 

 ment shown in Figure 31, the forms being a(100), ?n(110), c(001), 

 r(112), r (I12), n(101), n (101). These are iron-black in color and 

 have hexagonal and triangular markings on the basal pinacoid. 

 They have a distinctly red streak like that of pyrargyrite. 



SHOSHONE COUNTY 



A gray mineral resembling polybasite has been noted in quartz of 

 ore from the Pilot mine, Murray, associated with gold and silver 

 tellurides and native gold. 



PEARCEITE 



Basic silver sulpharsenite, 8Ag 2 S.As2S3. Monoclinic, perihexagonal. 



BONNER COUNTY 



Pearceite, the arsenic analogue of polybasite, has been recognized 

 in ore from the Conjecture mine, Lakeview district, south of Lake 

 Pend d'Oreille. Several stages of mineralization were recognized 

 in this vein. The earlier mineralization consists of manganiferous 

 ankerite and sphalerite which is replaced by galena and tetrahedrite. 

 The galena is partly replaced by pearceite and both are later replaced 

 by anglesite. 59 



ENARGITE (158) 



Copper sulpharsenite, Cu 2 S.4CuS.As 2 S 3 . Orthorhombic. 



CUSTER COUNTY 



Enargite occurs in massive form as a primary constituent of some of 

 the ores on Dickens Hill, in the Yankee Fork district. 00 It has been 

 noted only in small amount in a few specimens. 



» 7 Portland Daily Oregonian, Dec. 13, 1864. Capt. John Mullan, Miners and Travelers Guide to Oregon- 

 Washington, etc. New York, 1865, p. 106. 

 «« J. Ross Browne. Mineral Resources of United States, 1868, p. 528. 

 •• Edward Sampson. Oral communication, 1922. 

 «> J. B. Umpleby. U. S. Geol. Survey, Bull. 539, p. 52, 1913. 



