THE MINERALS OF IDAHO 439 



half mile below Huntley's ranch, impure soda niter occurs as a con- 

 stituent of crusts of salts which contain also niter, epsomite, and 

 halite, all stained red by iron oxide. At the Abbie claim in the same 

 vicinity thin seams of crystalline salts occupying cracks in rhyolite 

 consist of soda niter, niter, epsomite, and mirabilite. On the Dorothy 

 claim the soda niter occurs with mirabilite and epsomite in veinlets 

 3 to 5 mm. thick in rhyolite and it is also abundant in the surface 

 soils. On Jump Creek, 10 miles east of Sucker Creek, soda niter 

 occurs similarly with epsomite and mirabilite in crevices. 40 



NITER (684) 



POTASH NITER, SALTPETER 



Potassium nitrate, KN0 3 . Orthorhornbic. 



Niter has been found in small amounts in soils and in cracks 

 in lavas in several places in Idaho and some saline claims have been 

 located and some work done. The deposits all appear to be very 

 superficial and of small extent and the niter probably is nowhere 

 present in commercially valuable amount. 



BLAINE COUNTY 



In Blaine County, 9 miles east of Soldier, niter occurs in depres- 

 sions or small cavities in rhyolite, and also impregnating soil at the 

 bases of cliffs. The material, which is said to be present in con- 

 siderable quantity, is essentially potassium nitrate with a little 

 soda and lime in some samples." 



CLARK COUNTY 



Specimens of crystalline granular niter collected by H. T. Stearns 

 of the United States Geological Survey have been examined. These 

 were collected from cracks and crevices in basalt at the backs of 

 lava tunnels near the United States Sheep Experimental Station, 

 6 miles northeast of Dubois. When the niter is removed the cracks 

 fill up again in the course of a year or two. The niter is white and 

 crystalline-granular and does not alter on exposure to air. Under 

 the microscope it is homogeneous with the usual optical properties. 

 An analysis gave the following results. 



<° G. R. Mansfield. U. S. Oeol. Survey, Bull. 620, p. 19, 1916. 

 «' Q. R. Mansfield. U. S. Gcol. Survey, Bull. 620, p. 28, 1916. 



