IRON ORES. 



Franklinite ( an American ore). 



Colour dark black. 

 Streak dark brown. 

 Structure brittle. 



Composition 66 per cent, peroxide of iron, manganese, 

 and zinc. 



In appearance is something like magnetic iron, but less 

 metallic. 



Copperas (green vitriol). 



Colour greenish white. 



Lustre glassy and subtransparent. 



Structure brittle . 



Contains 25 per cent, of oxide of iron, also sulphur and 

 water. 



It is formed by the decomposition of iron pyrites. 



Vivianite. 



Crystallization oblique prisms. 

 Lustre pearly or glassy. 

 Colour deep blue to green. 

 Streak blue. 

 H. 1-5 to 2; S.G. 26. 



Composition 42 per cent, protoxide of iron, phos- 

 phoric acid, and water. 



Becomes opaque before the blowpipe. 

 Spathic Iron (iron spar, carbonate of iron). 



Sometimes massive, with a crystalline structure 



Crystallization hexagonal, rhombohedral fo. 



Lustre glassy or pearly. 



Colour yellowish grey to rust colour ; becomes brown- 

 ish red to black on exposure. 



Streak uncoloured. 



H. 3 to 4-5 ; S.G.- -3-7. 



Composition 62 per cent, of protoxide of iron, car- 

 bonic acid, &c. 



