CLASS IT. OllDERS. 397 



VII. ORDER, GEM. 



Non-metallic. 



No metallic adamantine lustre. 



Streak uncoloured. 



H. = 5-5 ... 10-0. 



G. = 1-9 ... 4-7. 



H. = 6-0 and less : tessular, G. = 3-1 

 and more ; or G. = 2'4 and less, and no 

 traces of form and cleavage. 

 G. under 3-8 : no pearly lustre upon faces 

 of cleavage. 



VIII. ORDER. ORE. 



No green streak. 

 H. 2-5 ... 7-0. 

 G. =3-4 ... 7-4-. 



Metallic : colour black. 

 Non-metallic : lustre adamantine or imper- 

 fect metallic. 

 Streak yellow or red : H = 3-5 and more, 



G. = 4-8 and more. 

 Streak brown or black : H. = 5-0 and more ; 



or cleavage monotomous. 

 H. = 4-5 and less : streak yellow, red or 



black. 



H. 6-5 and more, and streak uncoloured : 

 G. = 6-5 and more. 



