NO. 1867 CRYSTALLIZED VARI8CITE FROM UTAH.—8CHALLER. 427 



On the basis of the above angular values the following comparison 

 of the axial ratios is made: 



Comparison of axial ratios (second orientation). 



Mineral. 



Variscite 



Scorodite 



Strengite 



Phosphosiderite (1) 

 Phosphosiderite (2) 



0. 8379 

 .8658 

 .8652 

 .8229 



.8772 



0. 9181 

 .9541 

 .9827 

 .9381 



1.0660 



The agreement in values is much closer than for the first orienta- 

 tion, but the prism form loses its simple indices. It must be said, 

 however, that this orientation has much to commend it and may 

 perhaps be chosen in the future as the best one for the mineral, 

 especially when the properties of strengite and barrandite are better 

 defined than they are at present. 



THIRD ORIENTATION. 



A third orientation is still possible, namely, by considering the 

 large face as the basal pinacoid. Though the angular values derived 

 from this orientation show a close agreement, such a habit is entirely 

 at variance with that of all the other minerals of this group, and the 

 choice of orientation must be left tothe first or second one. 



By making the large face the basal pinacoid and taking m as (101) 

 and e as (021), the following comparison is obtained: 



Comparison of angles (third orientation) . 



From these values the following axial ratios are obtained: 



Comparison of axial ratios (third orientation). 



Mineral. 



Variscite 



Scorodite 



Strengite 



Phosphosiderite (1) 

 Phosphosiderite (2) 



