70 PHYSIOGRAPHY. 



Blende. 



3. Fig. 67. 



Pon a 135 00' 00" ) 



a on e 125 15 52 > HAUY. 



c on c 109 18 16 ) 



4. Dodecahedron with the obtuse solid angles deeply trun- 

 cated, so as to give rise to an octahedron with its edges re- 

 placed by tangent planes, (fig. 62. P. I.) 



5. Regular octahedron. 



6. Tetrahedron. 



7. Regular octahedron with its edges and angles replaced 

 by tangent planes. 



8. Cube. 



9. Tetrahedron with its angles replaced by tangent 

 planes. 



10. Tetrahedron with its angles replaced by three planes 

 resting on its edges, (fig. 55. P. I.) 



Cleavage parallel to the primary faces, perfect. 



Fracture conchoidal. Some yellow varieties are phos- 

 phorescent by friction. 



Lustre adamantine. Color green, yellow, red, brown, 

 black, none of these bright. Streak white to reddish- 

 brown, corresponding to the color, Transparent. . . trans- 

 lucent, 



