442 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



M, — 2f (152). Observed but once as a distinct face with fair reflec- 

 tion (Figure 6). 



<p p 



Crystal 7 -42° 01' 75° 21' fair. 



Calculated -42 22 75 07 



It, —24 (2~41). An important form, found fourteen times on nine 

 crystals, faces distinct and often large, not very lustrous, and reflec- 

 tions often confused with that of (401) in twin position (Figures 3, 4, 

 7, and 8). 



