576 E. T. Wherry — New Occurrence of Carnothte. 



(TI0. 2 ) 2 (Y0 4 ) 2 , which is identical with that indicated by the 

 previous work on carnotite.* Hillebrandf has shown, to be 

 sure, that different samples of the mineral from Colorado vary 

 rather widely in composition, yet throughout his and the other 

 published analyses the ratio 1:2:1 for the three oxides is 

 continually indicated. This is shown by the following table, 

 in which the analyses have been recalculated to 100 per cent 

 after deducting, as probably foreign to the mineral, the iron 

 and phosphoric acid and also the water, whose amount is so 

 variable that its role is uncertain. 



Analyses of Carnotite {Recalculated). 



12 3 4 5 6 



V 2 5 21-16 21-28 22-03 22*72 21'50 21*89 



U0 3 ._. 67-41 66-85 65*44 64*72 64'70 65*48 



R'O 4-59 4-12 4-73 5'86 



R' 2 11-43 1T87 7-94 8'44 9'07 6*77 



100-00 



100-00 



100-00 



100-00 



100*00 



100-00 



i 



8 



9 



10 



Calculated 1:2:1 



21-85 



23-05 



23*2 



21-1 



22*44 



21-34 



65-27 



65-68 



66-2 



69-8 



70-65 



67*64 



6-48 



6*40 



3-2 



4-4 



6-91 







6-40 



4-87 



7-4 



4-7 







11-02 



V 2 _ 



U0 3 



R'O 



R' 2 



100-00 100-00 100-0 100-0 100-00 100-00 



1, 2, Colorado: Friedel and Curnenge. Bull. Soc. Franc. Min., vol. xxii, 

 p. 26, 1899 and elsewhere ; considerable R"0 probably present but overlooked 

 and weighed with the R'oO (Hillebrand). 



3-8. Colorado : Hillebrand, Bull. U. S. Geol. Survey, No. 262, p. 25, 1905. 



9, South Australia : Crook and Blake, Min. Mag., vol. xv, p. 271, 1910. 



10, Pennsvlvania. The results of the present study. 

 Calculated, a, for E" = Ca ; b, for R' = K. 



The cause of the variations in these analyses is not altogether 

 clear; but, after all, they are perhaps no greater than is to be 

 expected in view of the non-homogenous character of the sam- 

 ples examined, and the difficulties of the analytical procedure. 

 In any case the evident similarity of the material from the 

 three widely separated localities justifies no other conclusion 

 than that we are dealing with a definite mineral species, of the 

 formula (Ca,K 2 ) (U0 2 ) 2 (Y0 4 ) 2 . 



This formula at once suggests relationship with the uranite 

 or autunite group, the members of which contain, however, 

 from 8 to 10 molecules of water of crystallization. The 

 amount of water found in the various samples of carnotite 



*Cf. Crook and Blake, loc. cit. fLoc. cit. 



