106 Penjield and Foote — Bixbyite, a new Mineral, 



sulphur dioxide. It was weighed as Ti0 2 . From the filtrate 

 from the basic acetate precipitation, manganese was precipi- 

 tated with excess of bromine water. The precipitate, after 

 filtering, was dissolved in a solution of sulphur dioxide, pre- 

 cipitated as phosphate and weighed. Magnesium was precipi- 

 tated from the first manganese filtrate as phosphate. 

 Following are the results of the analyses : 



I. II. Average. Ratio. 



Si0 2 1-24 1-19 1-21 



A1 2 3 2*57 2-48 2*53 



Fe 2 3 47-81 48-15 47*98 -300 



Ti0 2 1-62 • 1-78 1-70 -022 



MnO 42-08 42-02 42-05 *592 



MgO 0-12 0*09 0-10 -002 



Avail. O.... 4-37 4-39 4-38 -274 



99-81 100-10 99-95 



The silica and alumina are regarded as impurities, as only a 

 trace of them went into solution when the mineral was treated 

 with hydrochloric acid. In preparing the mineral for analysis, 

 a variation in specific gravity was observed, owing to the fact 

 that some of the dark particles were buoyed up by impurities, 

 but in order to obtain sufficient material for analysis, it was 

 necessary to include some of the lighter portion. It is prob- 

 able from the results of the analysis that some topaz was 

 present, for the ratio of silica to alumina is about 1 : 1 and 

 topaz is intimately associated with the bixbyite. 



Leaving silica and alumina out of account, two formulas are 

 possible. Considering the titanium as Ti 2 3 , the oxygen 

 derived from the Ti0 2 , 0*16 per cent, plus the available oxygen, 

 4*38, total 4-54 per cent, is about sufficient to convert the MnO 

 into Mn 2 3 , the amount required for 42*05 per cent, MnO being 

 4-74. The composition therefore can be expressed as R s 3 

 where K = Fe, Mn and a little Ti. The proportion of Fe to 

 Mn is 1 : 0*99 or almost 1:1, so that disregarding Ti 2 O s , the 

 composition is FeMn0 3 . If the mineral is an isomorphous 

 mixture of Fe 2 3 , Mn 2 3 and Ti 2 3 we should expect it to be 

 rhombohedral and to belong to the hematite, corundum and 

 menaccanite group, and also it is not probable that the Fe and 

 Mn would be present in the proportion 1:1. 



As the mineral is isometric, it seems more reasonable to 

 regard it as a compound having essentially the composition 

 FeO . Mn0 2 and related to the isometric mineral perofskite, 

 CaO . Ti0 2 . On this basis, the results of the analysis may be 

 put in the following shape : 



