A. J. Jloses — Crystallization of Luzonite. 



279 



From still another specimen of massive luzonite, bnt resting 



upon it rather than growing from it, was a little group of 



black lustrous crystals, the best of which, crystal No. 4, shown 



in fig. 4:, measured T % XiXf mm in the directions a, b, d, which, 



3 4 



while differing from all described enargite crystals in the pres- 

 ence of a pyramid, P = 223, as its most prominent terminal form, 

 connects directly with crystal No. 3 by the fact that this pyramid 

 and all the other forms of the crystal are prominent on crystal 3. 

 Both crystals were measured in the two-circle goniometer. 

 Crystal No. 3 yielded good to fine signals from twenty-one 

 faces and poorer ones from four others, while crystal No. <± 

 yielded good signals from twelve faces and poorer from two 

 others. The average results tabulate as follows : 





Crystal. 



Number 

 faces. 



Measured angles. 



Computed enargite angles. 



Forni. 







P 



<P 



P 



C (001) 



3 



1 





0° 





0° 



(i 



4 



1 





0° 



_ _ 







b (010) 



3 



1* 



0° 



89° 49*' 



0° 



90° 



a (100) 



3 



2 



90° 04V 



90° 



90° 



90° 



u 



4 



o* 



Approx. 90° 



90° 











m (110) 



3 



4 



49° 02' 



90° 



48°59'47" 



90° 



a 



4 



4 



48° 57' 



90° 









h (120) 



3 



4 



29°56|' 



90° 



29° 54' 13" 



90° 



a 



4 



1 



30° 03' 



90° 







I (130) 



3 



1 



20° 50' 



90° 20° 58' 38" 



9o° 



s(OH) 



3 



1* 



0° I' 



39° 40' 0° 



39° 3(3' 16" 



5 (051 



3 



2 * 



0° 



76° 18' j 0° 



76° 24' 40" 



7c (101) 



• 3 



2 



90° 5' 



43° 39' 90° 



43° 34 ; 56" 



u 



4 



2 



90° 



43°40^ 







P (223) 



3 



4 



49° If 



39° 51' 48° 5 9' 47" 



40° 3' 16" 





4 



4 



48° 59' 



39° 56' ' 







* Poor signals. 



