THE MINERALS OF IDAHO 419 



LEMHI COUNTY 



Pyromorphite occurs as minute yellow-green to green crystals 

 coating quartz in specimens from the Isis claim, Mineral Hill district, 

 7 miles north of Shoup. 



SHOSHONE COUNTY 



Pyromorphite has been found in fine specimens in a number of 

 mines in the Coeur d'Alene district. Many of the specimens from 

 this district were equal to those supplied by any other locality in 

 the world and the only other locality in the United States com- 

 parable to the Coeur d'Alene in the beauty and excellence of its 

 specimens is the Phoenixville region in Pennsylvania. 



In this county the pyromorphite is usually characteristic of the 

 upper portion of the oxidized zone. In color it is most commonly 

 some shade of pale yellow-green or green, although colorless, pink, 

 gray, or brown varieties are occasionally found. The mineral 

 generally forms drusy crusts of small crystals coating rusty rock 

 fragments. These often show only the unit prism and basal pinacoid 

 (fig. 136), although narrow beveling faces of the unit pyramid are 

 frequently present (fig. 133) and, very rarely, narrow faces of the 

 second order prism. The prism faces are usually deeply furrowed 

 horizontally and are frequently curved or bulging giving the crystal 

 a barrel shape. In many specimens the tips differ sharply in color 

 or transparency from the balance of the crystal and the basal pinacoid, 

 while sometimes smooth and brilliant, is often replaced by a cup- 

 shaped depression. Some crystals fray out at one or both ends into 

 bundles of fibers and rarely the mineral is wholly fibrous. Parallel 

 growths are common and frequently large aggregates in parallel 

 position taper to a small point by which they are attached. Im- 

 perfectly crystalline masses occurred in the Senator Stewart mine 

 and wholly massive pryromorphite of vitreous appearance and 

 conchoidal fracture occurred in the Blackbear mine. Smooth small 

 botryoidal coatings of pyromorphite occurred in the Quaker tunnel. 

 Frequently the crystals are imperfect and occur as branching forms 

 of a green color which coat dark iron or manganese stained rock 

 fragments and bear some resemblance to mosses, green lichens, or 

 other plant growths. 



As a rule the pyromorphite occupies cracks in low-grade gangue 

 or in wall rocks of small fissures somewhat removed from the richer 

 ore bodies, the lead of the pyromorphite having apparently migrated 

 somewhat in solution. Because pyromorphite-bcaring portions 

 of the mines were seldom rich enough to work the mineral lias not 

 been entirely removed and may still be found in the old surface 

 workings of some mines. Good specimens are still available in 

 several places, notably the Little Giant, Blackbear, and other mines • 



This is the only lead mineral which has been found in the district 



