302 



0. C. Farrington — Azurite from Arizona. 



orthopinacoid making up the table and the sun-rounding faces 

 the bezel, %. 5. Another peculiarity is that all the prominent 



angles are near 45° or 90°. On this crystal, the new form K, 

 12-105, -^--f, was observed and its symbol determined from 

 its position in the zone ah, and the following measurements. 





Meas. 



Calc. 



K~a, 12-10-5* 100 



39° 55' 



39° 48' 



K~\ 12-10-5^221 



95° 57' 



96° 16' 



K.,m, 12-10-5^110 



19° 38' 



18° 53' 



From the close relation of this symbol to that of the form G, 

 321, which occurs on other crystals of this habit, it was at first 

 thought that they should be the same, but this face was found 

 to lie outside the zone md, and though it was impossible to 

 obtain accurate measurements, all varying from 1° to 2°, the 

 symbol given accords so well with the mean of all, that there 

 can be little doubt of its correctness. The crystal shown in 

 fig. 6 is like the one last mentioned, except in being more 

 elongated in the direction of the vertical axis and in having 

 the orthopinacoid less prominently developed. In fig. 7 the 

 general habit is the same but the crystal is more highly modi- 

 fied. The latter represents a type of common occurrence, the 

 crystals never being completely developed and with the faces 

 often distorted in size and shape, so that they appear as clusters 

 of faces of nearly equal size, without apparent symmetry. 

 They are usually attached along the zone of clinodomes, the 

 basal plane and domes showing striations parallel to the edge of. 



In figs. 6 and 7 the new forms Q, 223,- 1 and G, 321, 3-f 

 will be observed. 



The form Q also occurred on the lath-shaped crystals, and as 

 more accurate measurements could be made on these, will be 

 described under that head. The symbol of G was determined 

 from its occurrence in the zones ah and md and from the fol- 

 lowing measurements. 



