201 



opaque. A distinct cleavage in two directions (transverse on 

 the plates), is characteristic. 



The small crystals are too imperfect to make measurements 

 possible and on the plates no edge planes were found, so the 

 crystallographic material was very poor. 



In both cleavage planes there is parallel extinction in the 

 direction of the edge between them. The optic axial plane is 

 parallel with the edge between the cleavage planes. The angle 

 between these was found to be about 85°. 



The specific gravity was determined to be 3"084. The 

 hardness is 5 — 5V2. The analysis is by cand. polyt. Chr. 

 Christensen, who states the following: 



«The mineral was decomposed with hydrochloric acid; 

 in the filtrate from the silica was precipitated with ammonium 

 sulphide; the precipitate was dissolved in hydrochloric acid 

 and iron precipitated with sodium acetate. In the filtrate from 

 this yttrium was precipitated with oxalic acid. The precipitate 

 of yttrium oxalate was ignited, dissolved in nitric acid and 

 precipitated with ammonia. In the filtrate from the pre- 

 cipitate by oxalic acid manganese was precipitated with 

 sodium carbonate.» 



"Calcium and sodium were found in the usual way in 

 the filtrate from the precipitate by ammonium sulphide.» 





per cent 



5г02 



51-44 



T,0, 



2-40 



^eO 



2-01 



ЧпО 



11-69 



ЪО 



20-53 



ЩО 



0-13 



\Ч.,0 



9-50 



4,0 



2-25 



equiv. 



II. 



per cent 



85-7 



2-l(F0) 



2-8 



16-5 



36-2 



0-3 ) 



15-3 1 

 12-5 J 



99-95 





51-79 





2-19 





2-00 ( 



57-9 



11-63 





20-13 





0-12 



27-8 



9-82 

 2-32 





100-00 



per cent 

 54-09 



0-10 



4-33 



29-82 



9-18 



2-48 



100-00 



III. 



equiv. 

 90-1 



0-\A(FeO]] 

 6-1 

 53-3 



14-8 

 13-8 



59-5 



28-6 



IV. 



per cent 



53-61 



0-10 



4-33 



29-83 



9-55 

 2-58 



100-00 



