THE MINERALS OF IDAHO 403 



In addition to the above constituents the analysis showed traces 

 of ferric oxide, alumina, and phosphoric oxide. Earlier tests did 

 not definitely identify helium as a constituent of the mineral, but 

 later tests made by more improved methods showed helium to be 

 present in the mineral. 14 



The molecular ratios of the above analysis may be combined as 

 follows: 



FeO 0.040 U0 2 0.038 C0 2 0.005 



CaO .052 Th0 2 .015 Si0 2 .010 



BaO .002 Zr0 2 .002 Ti0 2 .488 



SrO .001 



PhO .001 



. 055 . 503 



. 096 



This leaves Yt 2 O 3 -0.011, U0 3 - 0.116, and H 2 O-0.111 un- 

 grouped. On this basis the mineral may be simplified to : 



RO 0.096 



Yt 2 3 



Ro 2 



U0 3 



Ti0 2 



H 2 



Without any further combination this yields the approximate 



formula : 



9RO.Yt 2 O 3 .5RO 2 .llUO 3 .46TiO 2 .10H 2 O 



The figures for KO and U0 3 are not very near whole numbers, 

 but this need cause no disappointment, as the whole calculation 

 rests on the assumption that the iron is in the ferrous condition. 

 Although this assumption has certain analogies to support it and 

 is given preference, it would not be entirely unreasonable to assume 

 that part or all of the iron is in the ferric condition. The question 

 can not be settled experimentally in the presence of uranium in two 

 states of oxidation. If all of the iron is assumed to be present as 

 ferric iron the following percentages and molecular values are ob- 

 tained in place of those first given: 



Per cent Molecular values 



FeO None. 



Fe 2 3 3.20 0.020 



U0 2 18.40 .068 



U0 3 25.10 .089 



Appropriate grouping now leads to the approximate formula: 



2RO.R 2 3 .3R0 2 .3U0 3 .18Ti0 2 .4H 2 



The bases are apparently present as titanates, metatitanates, or 

 "uranotitanates, but an exact evaluation of the relative proportions 



i« Wells, R. C. Note on brannerite, Journ. Franklin Inst., vol. 189, No. 6, pp. 779-780, June, 1920. 



