334 



Spodumene and its Alterations. 



To confirm the uniformity of these relationships, the atomic 

 ratios have been further calculated in the same way from four 

 of the individual analyses. 





VIII 



X 





XI 





XII 





Si 



976 12.2 



987 



12.1 



975 



12.2 



969 



12. 



Al(Fc) 



456 5.7 



481 



6. 



436 



5.5 



496 



6.1 



Na (H, K) 



474 6. 



444 



5.5 



546 



6.8 



458 



5.7 







2954 37. 



2983 



37. 



2956 



37. 



2988 



37. 



H (as aq.) 



161 2. 



161 



2. 



161 



2. 



161 



2. 



The atomic ratios of the elements which constitute E 1 , in these 

 analyses, are given in the following table. 



VIII X XI XII 



Mg, Ca 60 3 34 2 110 5 62 



Na r :-:;s U! 



K, Li 



60 

 293 



102 

 19 



34 

 238 

 113 



59 



110 



222 



155 



59 



5 



10 



184 

 129 



3 



4 

 10 



H (basic) 



From these figures, it may be inferred that the proportion of 

 the several elements is somewhat indefinite and irregular, and 

 that a sufficient complement of basic hydrogen is always present. 

 The amount of sodium diminishes through the varieties to the 

 lowest degree in Aglaite (XII), in which both potassium and 

 hydrogen rise to the maximum ; and that is the variety which 

 possesses the physical characteristics most akin to those of .the 

 potash-bearing hydromicas. 



From the atomic ratios 



E : fi : Si : Q : Aq. 



6 3 12 37 1 



the formulas* of Cymatolitc, empirical and rational, are found 

 to be those of a normal silicate — 



* According to the old system — 



(s (I -UO + \ KO, Na 0)4 jf ■& O 3 ) 3 Si 0\ 



From my analysis of Aglaite, P. Groth (Zei's. f. Kryst. u. Min., Ill, 1878) deduces the 

 formula — 



(H, Na, K) 10 Al° Si 2 " O 05 . 



