GEOLOGICAL SOCIETY. 



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Light gray metallic color, H. 7| and more. Ex- 

 amples — gray manganese, Br. 



Semi-metalic black color : black streak, pyro- 

 lusite and psilomelan, or G. 4, 4 and more. Ex- 

 amples— manganite, brownite and chromate 

 of iron, Jam. 



Common lustre : H. from 1 to 9, G. from 2, 1 to 8, 1. 

 H. from 1 to 2§ : black streak, and G. below 



3, 4, as in black cobalt ochre. 

 H. from 2 1 to 4 J : black, brown, red or yellow 



streak, and G. from 2, 3 to 4, 8, as in pitchy 



iron ore, (Phillips,) and yellow iron ore, Br. 

 H. from 4 1 to 6 : black, brown, red or yellow 



streak, and G. 3 or more, as in triplit, lepido- 



croquite, carphosideute, Br. 

 When G. from 5 to 6, the streak is gray, as in 



yellow antimony, and when tesseral it is even 



uncolored. 



H. from 6 to 8 : G. 3, 5 and more, as in pyro- 

 chlore, polymignite, uncleavable cerium ore, 

 uncleavable uranium ore, black manganese ore. 



When G. is less than 4, the streak is yellow, 

 brown, black or gray, as in tephroite, lievrite, 

 botryoidal zinc and stilpnosiderite. 



When H. is from 8 to 9 : G. is 4, 1 and more, 

 as in gadolinite, ostranite, Br., tantalite. Fur- 

 ther examples are found in rutile, cerin, brown 

 iron ore, wolfran, red copper ore &c. 



