4S6 DESCRIPTIVE MINERALOGY. 



TROOSTITE. 



Ferruginous Silicate of Manganese. Tiunnsm. 



Colour pale asparagus-green, yellow, grey and reddish brown. Crystallized and massive. 

 Primary a rhombohedron. PonPllS^. Lustre vitreous. Transparent to translucent. Hard- 

 ness 5.5. Sp. gr. 4.00 to 4.10. Before the blowpipe, it melts on the edges. Composed 

 of silica 30.65, protoxide of manganese 46.21, peroxide of iron 15.45, moisture and carbonic 

 acid 7.30. 



Sterling, New-Jersey, with franklinite. 



TUNGSTEN. 



Tungstate of lime. Dana and Phillips. 



Colour white, grey, yellowish and reddisll brown. Streak white. Crystallized and massive. 

 Primary an octahedron with a square base. Lustre vitreous, inclining to adamantine. Semi- 

 transparent to translucent. Hardness 4.0 to 4.5. Sp. gr. 6.08. Fuses with difficulty before 

 the blowpipe. Composed of lime 19.40, tungstic acid 80.42. 



Monroe and Trumbull, Connecticut. 



TUNGSTIC OCHRE. 



Yellow oxide of Tungsten. Clcavchind. 



Colour orange or chrome-yellow to yellowish grey. Massive ; earthy and pulverulent. Soft. 

 Sp. gr. 6.0. Assumes a green hue when strongly heated. Composed of oxygen 13.55, 

 tungsten 86.45? 



Lane's mine in Monroe, Connecticut, with tungsten and wolfram. 



URANITE. 



Green Oxide of Uranium. Cleavcland. 



Colour yellow and green. Crystallized and massive. Primary a right square prism. Lustre 

 pearly upon the face P. Transparent to opaque. Hardness 2.0 to 2.5. Sp. gr. 3.12. 

 Composed of phosphoric acid, lime, oxide of uranium and water, with traces of fluoric acid 

 and ammonia, etc. 



Middletown, Connecticut, with columbite, etc. ; Cheslenleld, Massachusetts, with albite. 



