478 W. E. Hidden and J. B. Mackintosh — Yttria and 



twenty kilos were found in all. Upon being broken open they 

 are of an olive-green color, tending in places to a drab shade. 

 Peculiar minute ragged lines permeate the mineral in all direc- 

 tions, causing an apparent muddiness or semi-opacity. No crys- 

 tals have as yet been observed, but a seemingly orthorhombic 

 symmetry was apparent in some of the masses. The mineral 

 breaks easily in two directions with a shell-like fracture, but 

 separates into small flakes very readily. (Gadolinite is broken 

 only with difficulty.) Nothing like a cleavage has been 

 noticed. A thin white crust of a mineral related to teno-erite 

 occupies the cracks in the mineral and this is equally true con- 

 cerning the gadolinite of the locality as Genth has already 

 noted. We have named the mineral yttrialite, in allusion to 

 the prominent part played by the yttria earths in its composi- 

 tion. 



The specific gravity is 4'575 ; hardness= 5-5*5. It is readily 

 soluble in hydrochloric acid. When heated over the Bunsen 

 flame it decrepitates violently, and falls to powder upon being 

 ignited over a blast, becoming snuff -brown, infusible and in- 

 soluble. These characteristics serve to at once distinguish 

 it from gadolinite, which has specific gravity from 4'2 to 

 4 # 3 (Texas varieties), and which when heated glows vividly 

 and swells into ragged fragments. The analysis shows several 

 fractions of the yttria earths (A, B, C, D), which were sepa- 

 rated by successive precipitations with sodium sulphate. The 

 atomic weight of each fraction was determined, showing 

 successive increase with each separation. The fractionation 

 was discontinued after the fourth separation, as the amount 

 of material was getting very small, but the atomic weight 

 shows that the lanthanum and didymium are still mixed with 

 an earth of higher atomic weight. The results obtained are as 

 follows : 



SiOo 29 



PbO... 



Th0 2 12 



MnO 



FeO 2 



CaO 



Alo0 3 



:e 2 3 1 



(A)Y 2 O s 22 



(B)Y 2 3 5 



(C)Y 2 3 . 4 



(D)Y a O s 14 



(LaDi) 2 3 , etc 2 



U0 3 



Isrnicion loss. 







Oxyg 



en ratio. 



•17 % 





97-234 = 4 



•854 





0-383 ] 



•00 





9-108 1 



•77 





1-084 1 



■89 





4-014 | 



•60 





1-071 1 



•55 





1-617 | 



•86 





1-722 }* 72*918 = 3 



Atomic weight. 







•67 = 



110-3 



25-320 





•30 = 



110-53 



5-910 





•50 = 



134-9 



4-860 





•03 = 



120- 



14-616 





•94 = 



162- 



2-370 





•83 





0-843 J 





•79 









99-754 



Total yttria earths = 46-50 % erbia spectrum distinct. 



