THE MINERALS OF IDAHO 49 



of sulphur springs, which range from the size of a washbasin to some 

 which are large enough for a good-sized swimming pool. The water 

 is milky from precipitated sulphur and is acid, much carbon dioxide 

 and hydrogen sulphide being given off. The bulk of the sulphur, 

 which is associated with small crystals of gypsum, forms the cement 

 of a fault agglomerate or breccia composed of fragments of tuff, lime- 

 stone, and quartzite. Small pyramidal crystals are found lining 

 cavities of crystalline and amorphous masses in the interstices of the 

 breccia. The crystallinity is shown by the spherical radiated figures 

 formed upon some surfaces obtained by breaking, while the smooth 

 or conchoidal fracture on other surfaces serves to indicate the amor- 

 phous variety. A rather spectacular form, namely, stalactites in 

 vertical crevices traversing the breccia, occurs in the south wall of 

 the quarry on the Wood Canyon side of the divide. This variety 

 has an almost canary-yellow color on fresh fracture, which changes 

 rapidly on exposure to dull, submetallic gray. Much of the low- 

 grade ore also has this gray color. Air bubbles in many of the sta- 

 lactites may indicate that the sulphur was exuded in liquid form. 

 Alum occurs rarely in the deposits. 7 



BLAINE COUNTY 



Powdery sulphur occurs, partly filling little cavities left by the 

 removal of pyrite in quartz of the oxidized portions of the Clipper 

 Bullion vein, Mineral Hill district. This mineral was found by Mr. 

 D. F. Hewett in a prospect l 1 ^ miles southeast of Bellevue associ- 

 ated with anglesite and wulfenite. 



CUSTER COUNTY 



A specimen of cavernous earthy limonite from the oxidized ore 

 about 30 feet below the surface in the Lost Packer mine contained 

 residual friable masses of chalcopyrite and pale yellow druses of 

 minute crystals of native sulphur. 



SHOSHONE COUNTY 



Sulphur has been noted in the Caledonia and Hypotheek mines as 

 an alteration product of sulphides in the oxidized ores. In the upper 

 workings of the Caledonia mine native sulphur was a constituent of 

 a yellowish earthy material consisting largely of crushed quartz, with 

 a little limonite and bindheimite. The presence of sulphur in this 

 material was shown by its taking fire and burning with a blue flame 

 when placed on a hot stove. In the Hypotheek mine near Kingston 

 sulphur occurred as minute yellow globules inclosed in transparent 

 anglesite crystals lining cavities in galena. 



» K. W. Richards and J. H. Bridges. Sulphur deposits near Soda Springs, Idaho. U. S. Geol. Survey, 

 Bull. 470, pp. 499-503. 1911. 



