420 CHARACTERISTIC. CLASS II. 



Cleavage, Pr -}- os. 

 Streak red ... green. 



Prismatic Red Cobalt. J. ii. 184. 



III. IRON-MICA. Prismatic. 



Streak uncoloured ... blue. 

 H. = 2-0. 

 G. = 2-6 ... 2-7. 



1. PRISMATIC. Hemi-prismatic = 119 4'. Inclina- 

 tion = 10 53'. = 54 13'. 



2 

 Cleavage, Pr + . 



Vivianite. ii. 188. 



IV. GRAPHITE-MICA. Rhombohedral. 



H. = 1-0 ... 2-0. 

 G. = 1-8 ... 2-1. 



1. RHOMBOHEDRAL. Di-rhombohedral. 

 Cleavage, R 03. 

 Metallic. 

 Streak black. 



Plumbago. ii. 191. 



V. TALC-MICA. Rhombohedral, prismatic. 



Streak uncoloured ... green. 

 H. = 1-0 ... 2-5. 

 G. = 2-7 ... 3-0. 



Streak green : G. = 2-8 and less. 

 Hemi-prismatic: cleavage perpendicular 

 to the plane of inclination. 



1. PRISMATIC. Prismatic. P + os = 120 (nearly). 

 Cleavage, P os. 



