(28) 



Fig. 2. 



1 : 2,0214. 



a= 90°57V; 

 ^=z 113°2173' 



y=r 90' 2'. 



Fig. 3. 

 Triclino-pinacoidal . 



a :/';:c = 1,4909 



A= 9r 37; 



B=z 113°21V; 

 C= 90°27' 



Forms observed: c = jOOlj, strongly predominant and retlecting 

 ideally; a = jlOOj, and ?*=:|101|, nsnally developed equally broad 

 and also yielding sharp reflexes ; b ^= \010\, smaller, readily measur- 

 able ; m = \liO], large and lustrous; ^; = |113|, mostly narrow but 

 very lustrous ; sometimes as broad as m. 



Broad flattened towards |001|. The approach to monoclinic sym- 

 metry is also plain in this ease. 



Measured 

 a-.b = (100) : (010) =*89°33' 

 b:c = (010) : (001) =*88 567, 

 ; a = (001) : (100) =-66 387, 

 ; m = (010) : (110) =*35 597, 

 : r = (100) : (101) =*43 45 

 m == (001) : (110) = 75 46 

 ; m = (100) : (110) = 53 33 

 ?• =: (OOi) : (lOl) = 69 37 

 7?i=(10i):(110)= 65 20 



7?ï=rr(113):(110)= 60 59 

 : b = (lOi) : (010) =r 89 55 



: p = (101) : (113) = 50 53 



Calculated: 



c 

 b 

 a. 

 c 

 a 

 c 



r : 

 p: 



r 



r 



75^387; 

 53 337, 

 69 367, 

 65 11 

 60 447, 

 89 22 



