

CHARACTERS OF THE SPECIES. 



167 



RIGHT RECTANGULAR PRISM. 



Sp. Gravity. 



Various Observations. 



V7...5-8. 



2-7.. .3-0. 



2-0.. .2-2. 



2-3.. .2-4. 



3-02, 



6-0...6-3. 



3-3...3-8G. 



Cleavage parallel to M (Fig. 29.) eminent. 



Color white ; transparent. Lesser termi- 

 nal edges replaced by single planes so as 

 to extinguish the bases, and which incline 

 to each other, under an angle of 177 5'. 

 Color grey ; opake. 





'The faces of the four sided pyramid, by 

 which it is terminated, incline to each 

 other, under angles of 123 30' and 

 117 30'. 



