538 PalacJn and Warren — Chemical Composition and 



and it was generally only by a study of the form series of the 

 whole crystal that decision could be reached as to position of 

 the rhombohedral series. 



In the best crystals all the faces are brilliant and give sharp 

 images of the goniometer signal when not too narrow ; the 

 steeper forms are often developed as mere lines and the signals 

 are then apt to be dim. The frequent oscillatory striations, 

 however, do not seem to produce false faces, the signals of a 

 series of faces being generally quite distinct. All the crystals 

 examined bad been implanted by one end and were, therefore, 

 but singly terminated, but occasionally faces of very steep 

 forms belonging to the lower half of the crystal came within 

 the range of measurement of the goniometer. 



Twinning on the basal pinacoid was to be expected (see syn- 

 chisite below), but could not be established ; it would be more 

 or less completely concealed by the striated character of the 

 lateral surfaces of the crystal. 



Table II shows the forms found on the Quincy parisite. 

 These forms include practically all those previously discovered 



Table II.— Forms found on Quincy Parisite. 



Bravis-Miller. Gold. G 2 



Positive Ehonibohedrons 



! 



Negative 

 Rhornbohedrons 



C (0001) 







A (1014) 



1/4 



/3 (0.4.4.15) 



-4/15 



m (loio) 



oc 



B (4.0.4.15) 



4/15 



y 



(0227) 



-2/7 



a (1120) 



ocO 



C (3.0.3.11) 



3/1 1 



8 



(0.3.3.10) 



— 3/10 



Pyramids 





D (3.0.3.10) 



3/10 



e 



(0.9.9.25) 



— 9/25 



b (4.4.8.15) 



4/5 



E (5.0.5.16) 



5/16 



d 



(0338) 



— 3/8 



i (1123) 



1 



F (1013) 



1/3 



t 



(Oll2) 



-1/2 



I (11.11.22.27) 



11/9 



G (5.0.5.13) 



5/13 



6 



(0558) 



— 5/8 



n (5.5.10.12) 



5/4 



H (2025) 



2/5 



f 



(0334) 



-3/4 



t (4489) 



4/3 



e (1012) 



1/2 



V 



(0665) 



— 6/5 



q (1122) 



3/2 



i (8.0.8.11) 



8/11 



X 



(0554) 



— 5/4 



u (5.5.10.9) 



5/3 



J (7078) 



7/8 



P 



(0221) 



— 2 



r (2243) 



2 



9 ( 10il ) 



1 



■K 



(0552) 



— 5/2 



V (5566) 



5/2 



L (5054) 



5/4 



<r 



(0331) 



— 3 



p (1121) 



30 



M (4043) 



4/3 



* 



(0772) 



-7/2 



w (4483) 



40 



A (3032) 



3/2 



P 



(0441) 



— 4 



O (2241) 



60 



N (11. 0.11.6) 



11/6 



■A 



(0551) 



— 5 



Scalenohedron 





k (2021) 



2 



to 



(0661) 



— 7 



y (4.2.6.11) 8/11 



2/11 



P (1 1.0.11.4) 



S (3031) 

 Q (10.0.10.3) 

 R (4041) 

 T (5051) 



11/4 



3 

 10/3 



4 



5 









• 





V (6061) 



6 









