W.2. ISchaller — Crystallized Turquoise from Virginia. 37 



Comparison of measured and calculated angles, turquoise. 

 Angle 



Cryst. No. 1 Cryst. No. 2 Cryst. No. 3 Calculated 



110 



100 



45° 12' 



100 ^ 110 

 110 yy 110 

 110 /s 010* 

 Oil /^ IlO 

 Oil ^ 100 

 Oil ^ 110 

 Oil ^ 010* 



31 

 104 



37 

 107 



14 



14 



28 

 42 



31° 28 



44° 50' 



31 c 

 104 



25' 

 03 



38 

 105 



95 

 110 

 117 



39 

 15 

 33 

 00 



26 



31 



10 



104 



00 



40 



54 



105 



36 



95 



45 



109 



36 



119 



19 



* The faces of {010} gave very poor reflections. 

 Fig. 1. 



Fig. 1. Turquoise crystal, 

 fc {010}, a {100}, m{110}, Jf{ll0}, A; {Oil}. 



The forms a { 100 } and M \110\ are large and striated ver- 

 tically, a generally more striated than M. The prism m { 110} 

 is narrow and striated parallel to the edge (110) : (Oil). 

 Between m and h {Oil } lies an undetermined small face very 



