116 



PHYSIOGRAPHY. 



Polymignite. 



Cleavage, imperfect in the direction of the replacing 

 faces of the prism. Fracture conchoidal. 



Lustre metallic. Color black. Streak brown. Opake. 

 Hardness =6-5. Sp. gr. =4'8. 



1. Alone, upon charcoal, before the blow-pipe, it is unaltered. With 

 borax, it melts into an iron-colored glass. With salt of phosphorus, it is 

 with difficulty dissolved ; the glass appearing reddish in the reduction 

 fire, and the color not undergoing change from the addition of tin. With 

 soda, it becomes greyish-red, but does not melt. 



2. Analysis. 

 By BERZELIUS. 



Titanic acid 46-30 



Zirconia 14.1-4 



Oxide of iron 12 20 



Lime 4-20 



Oxide of manganese 270 



Oxide of cerium 5-00 



Yttria 11-50 



3. Its locality is Fredrichsvarn,Noiway, where it is found in Zircon- 

 sienite. 



4. Very small, iron-black crystals, of a prismatic form, which gave 

 with the common goniometer M on M = about 100, are found with the 

 Green Feldspar in sicnite, at Beverly, (Mass.) These prisms have their 

 lateral edges truncated. Hardness = 65. Streak brown ; lustre me- 



