COLUMBATKS. 1MK (SIMIATIIS, VANA1 ) A Tl .S 521 



northern Chili, southern 1'cru, and Bolivia. The nitrate is asso- 

 ciated with salt, gypsum, glauber salts, and generally borax. 

 Small amounts occur in Humboldt County, Nevada, and in San 

 Bernardino County, California. 



NITER 



Niter. Saltpeter, Potassium Nitrate, KNO ; K 2 O = 46.5, 

 N 2 O 6 = 53.5 ; Orthorhombic ; Type, Didigonal Equatorial ; ft : b : c 

 = .5843 : 1 : .7028 ; 100 A 110 = 39 35' ; 001 A 101 = 49 30' ; 001 A 

 Oil = 35 2'; Common forms, b (010), m(110), t(021), o(lll), 

 q(011); Cleavage, Oil perfect, 010 and 110 imperfect; Brittle; 

 Fracture, uneven; H. = 2; G. = 2.09-2.14; Color and streak, 

 white; Luster, vitreous; Subtranslucent ; a = 1.334; fJ = 1.505; 

 y = 1.506; y - a = .172; Optically (-); Axial plane = 100; 

 Bi a = b; 2E = 8 40'. 



B.B. Deflagrates on coal, yielding a violet flame (K), has a 

 cooling saline taste. Easily soluble in water, the solution yields 

 reactions for nitrogen, page 590. 



General description. Crystals are acicular, forming crusts or 

 silky tufts, as efflorescent crusts in dry regions. It is an oxidation 

 product found in soils, the result of the action of certain nitrifying 

 bacteria; the nitric acid thus formed combines with the bases, 

 with potassium to form niter, or with calcium to form nitrocal- 

 cite, Ca(N0 3 ) 2 . n (H 2 O). 



Niter is dimorphous, and in each form is isomorphous with the 

 two forms of calcium carbonate, calcite and aragonite. The or- 

 thorhombic form here, however, is stable at ordinary temperatures. 

 The hexagonal phase of soda-niter is stable at ordinary tempera- 

 tures and forms the natural occurring salt. 



Niter is of great commercial importance both as a fertilizer and 

 in the manufacture of gunpowder, the natural supply being so 

 limited that the salt is formed from Chili saltpeter by the interac- 

 tion of potassium chloride. 



Niter is associated to some extent with the sodium salts in the 

 Chili nitrate beds. It also occurs as an impregnation in the earth 

 on the floors of some of the caves in Kentucky and Tennessee. It 

 is often obtained by lixiviating such soils. 



