AZURITE. CRYSTALS FROM MINERAL HILL. 277 



The Azurite Crystals. 



Tlie azurite is mainly attached to the matrix obliquely 

 by one end of the symmetry axis; where the crystals are 

 not too crowded they are fiuely formed, aud among those 

 detached for measurement some are doubly terminated. 

 They vary in length from about *25 cm. to 1*75 cm., and 

 average perhaps *5 cm. 



Eighteen crystals were measured on a two-circle gonio- 

 meter, and several more were carefully examined for 

 additional features of interest. As some of the best crystals 

 were measured more than once and in different settings, a 

 large number of angular measurements were made and the 

 average values for the best faces are believed to have a 

 high degree of accuracy. A total of twenty-one forms, of 

 which one is new, was obtained ; doubtful and vicinal forms 

 are omitted from the lists but are dealt with below. The 

 forms are as follows, that marked by an asterisk being new: 

 c (001), b (010), a (100), m (110), w (120), I (023), f (011), 

 p (021), <£ (201), o- (101), (101), v (302), v (201), h (221), 

 5(111), P(223), k (2 21), y (121), R (2 41), X*(4 81), A (2'18'3). 



Combinations. — The following table gives the combina- 

 tions observed on the eighteen crystals : 



forms. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 



c (001) cccccccccccccccccc 



b (010) b . b 



a (100) aaaaaaaaa aaaaaaaaa 



m (110) m m m m m m in in in m m m in m m m m in 



zv (120) wwivwwwwwwwwivwwwivww 



I (023) I I I I I I -I I I I I I I I I I I I 



/(Oil) ffffffffffffffffff 



p (021) p p p p p p p ... p p p p p p p p p p 



<f> (201) (f> ... <f> <f> <f) (f> ... cj> <f) <£> <f> <f) ... <f> <f> <f> <f> </> 



<r (101) o" o" o" cr o" cr ... crcro-crcrcrcrcro-o-or 



6 ("i01) 066660066 6 66060966 



ri (302) r q -q 7] q rj rj q r] tj tj rj rj rj y tj 1] ^ tj 



