AZURITE CRYSTALS FROM MINERAL HILL. 



279 



probably present, and possibly F (207), A (l03), and B (504). 

 The following are the values obtained for p from the stronger 

 reflections. 



Form. 



Crystal. 



P 



Average. 



Calculated. 





( 



2 



8° 



14' 



\ 





[x (105) 



{ 



1 

 3 



18 



8 

 8 

 9 



6 

 14 

 39 



I 8° 33' 



9° 21' 





/ 



3 



12 



32 



\ 









12 



13 



24 







D (104) 



J 



15 



17 



13 

 11 



20 



40 



-12 25 



12 12 





, 



17 



11 



12 



/ 





F (207) 



i 



8 

 16 



14 

 14 



32 

 43 



i 14 37 



14 12 



A ("03) 



i 



8 

 12 



16 

 17 



44 

 11 



| 16 57 



16 50 



B (504) 





3 



50 



52 



50 52 



51 21 



Habit. — There are two habits of which Habit I is peculiar 

 to the crystals of specimens A and B. This habit [Plate V] 

 may be described as elongated parallel to the symmetry 

 axis and tabular on the plane of the b and c axes. Only 

 two pinacoids are present; of these c (001) usually has an 

 oblong face, never very large but fairly smooth and giving 

 good reflections; a (100) is a well developed form, oblong 

 or nearly square in shape and striated horizontally. The 

 unit prism m (110) is large and brilliant; it is sometimes 

 slightly striated vertically, but generally gives an excellent 

 reflection of the signal. The prism w (120), though always 

 present, is never large, being represented by a long, narrow 

 face ; iv (120) and iv' (120) generally meet in a long vertical 

 edge [Plate V, figs. 2, 3]. The orthodome zone is well 

 developed, but the negative orthodomes, particularly 

 (101) and v (201), are strongly striated parallel to the 

 zone edges and give multiple reflections; there is the usual 

 indefinite striated area between c and 0. Of the clinodomes 

 p (021) is usually small and almost triangular, f (011) is 



